Conference Programme and Abstracts

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SCIENTIFIC ORGANIZING COMMITTEE: Maurizio Busso Corinne Charbonnell Eva Grebel ¨ Susanne Hofner Uffe Jørgensen Franz Kerschbaum Ariane Lanc¸on Thomas Lebzelter Hans Olofsson (head) Robert Wing Peter Wood

LOCAL ORGANIZING COMMITTEE: Angela Baier Eveline Glassner Josef Hron Franz Kerschbaum Thomas Lebzelter (head) Walter Nowotny Roland Ottensamer Werner Zeilinger

CONFERENCE LOCATION: University Campus Vienna ¨ Horsaalzentrum Hof 2 Spitalgasse 2 1090 Wien Helpdesk phone: +43 650 5106910

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WELCOME TO VIENNA!

Dear participants! We would like to welcome all of you to the conference ”Why Galaxies Care About AGB Stars - Their importance as actors and probes”. This conference aims to build a bridge between AGB research and its application to the modelling of stellar populations and the chemical evolution of galaxies. Current developments and challenges on both sides will be discussed to reach an understanding of possibilities, limitations, and needs in both areas, and hence to improve our knowledge about the role of AGB stars in the context of galaxies. For more than 15 years AGB stars are now one of the main research topics at the Department of Astronomy at the University of Vienna. The questions addressed include atmospheric structure, variability, nucleosynthesis and mass loss. Currently interests focus on aspects of abundance determination, on the mid- and far-infrared range (participation in the HERSCHEL satellite) and on interferometry as a tool to study the dynamic atmospheres of long period variables. 250 years ago the first observatory of the University of Vienna was opened. During the conference dinner you will have the possibility to visit the second Vienna University Observatory built between 1874 and 1879. While being a place full of history it is today a vivid centre for modern astrophysical research. This conference is hosted by the Austrian Society for Astronomy and Astrophysics and the Department of Astronomy at the University of Vienna. The meeting is cosponsored by the IAU Working Group on Abundances in Red Giants. We thank the Robert Wing Support Fund, the Austrian Federal Ministery for Education, Science and Culture, the University of Vienna and several sponsors. We hope you all have an excellent and stimulating conference, and that you enjoy Austria and Vienna. The LOC

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SCIENTIFIC PROGRAM

MONDAY, 7 August 2006 08:00 - 09:00 Registration, posters can be put on display on boards 09:00 - 09:20 Opening of the meeting by the rector of the University of Vienna 09:20 - 09:55 AGB stars in stellar evolution models: concepts and problems (J. Lattanzio) 09:55 - 10:20 The evolution of super-AGB stars (L. Siess) 10:20 - 10:25 LOC announcements 10:25 - 11:00 Coffee break 11:00 - 11:15 Towards simulating the photometry, chemistry, mass loss and pulsational properties of AGB star populations in resolved galaxies (L. Girardi) 11:15 - 11:50 Inside AGB stars: elemental synthesis (M. Busso) 11:50 - 12:05 Light s-process element production in solar metallicity AGB stars (A. Karakas) 12:05 - 14:00 Lunch break 14:00 - 14:35 Convective and non-convective mixing (F. Herwig) 14:35 - 14:50 The impact of rotation on the nucleosynthesis in metal-poor AGB stars (T. Decressin) 14:50 - 15:35 Atmospheres of AGB stars: status and challenges of modelling (B. Gustafsson) 15:35 - 16:00 Coffee break 16:00 - 16:35 Laboratory data for cool star modelling (P. Bernath) 16:35 - 16:50 Spitzer/IRAC characterization of galactic AGB stars (M. Marengo) 16:50 - 17:05 The period-luminosity relation of mira variables in globular clusters (N. Matsunaga) 17:05 - 17:20 Recognition and classification of AGB stars by narrow-band TiO/CN photometry (R. Wing) 17:20 - 17:35 Theoretical AGB and post-AGB stellar models for synthetic population studies (A. Kitsikis) 18:30 - 20:30 Guided walking tour ”Vienna at First Glance”

TUESDAY, 8 August 2006 09:00 - 09:35 Measuring abundances on the AGB (V. Smith)

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09:35 - 09:50 AGB stars in globular clusters (T. Lebzelter) 09:50 - 10:15 Determination of element abundances (P. Hauschildt) 10:15 - 10:20 LOC announcements 10:20 - 11:00 Coffee break ¨ 11:00 - 11:35 Mass loss modelling (S. Hofner) 11:35 - 11:50 What drives the mass loss of oxygen-rich AGB stars (P. Woitke) 11:50 - 12:05 The dust sequence along the AGB (J. Blommaert) 12:05 - 14:00 Lunch break 14:00 - 14:35 Dust formation and growth (A. Andersen) 14:35 - 14:50 Molecular clusters in dust nucleation processes in circumstellar outflows of oxygen-rich AGB stars (B. Patzer) 14:50 - 15:05 Observation of water-ice in OH/IR stars (K. Justtanont) 15:05 - 16:00 Coffee break 16:00 - 16:35 The composition of dust surrounding AGB stars (R. Waters) 16:35 - 16:50 Spitzer/MIPS infrared imaging of extremely extended circumstellar shells (A. Speck) 16:50 - 17:05 VLTI - present and future prospects (A. Richichi) 17:05 - 17:20 Study of the circumstellar envelopes of AGB and early post-AGB stars (A. Castro-Carrizo) 17:20 - 17:35 Submm CO line observation and modelling from circumstellar shells (D. Teyssier) 17:35 - 17:50 What do we know about AGB mass loss? (L.A. Willson)

WEDNESDAY, 9 August 2006 09:00 - 09:35 Methods for determining AGB mass loss rates based on radio data (F. Schoier) 09:25 - 09:50 Methods for determining AGB mass loss rates based on infrared data (J. van Loon) 09:50 - 10:05 On the connection between mass loss and evolution of C-rich AGB stars (L. Mattsson) 10:05 - 10:20 On luminosity and mass loss of galactic AGB stars (R. Guandalini) 10:20 - 10:25 LOC announcements 10:25 - 10:50 Coffee break 10:50 - 11:15 Quantitative results on AGB mass loss rates (P. Wood) 11:15 - 11:30 Polychromatic interferometry of evolved stars with VLTI and VLBA (M. Wittkowski)

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11:30 - 11:45 Mass-loss rates of AGB stars in Sagittarius and Fornax (E. Lagadec) 12:30 - 20:30 Excursion to the Wachau

THURSDAY, 10 August 2006 09:20 - 09:55 Chemodynamical models of galaxy evolution (M. Tosi) 09:55 - 10:10 Yields from AGB stars and their impact on the chemical evolution of dwarf galaxies (S. Recchi) 10:10 - 10:25 AGB stars and starbursts (J. Gallagher) 10:25 - 10:30 LOC announcements 10:30 - 11:00 Coffee break 11:00 - 11:35 Star formation history as probed by AGB stars (E. Grebel) 11:35 - 11:50 AGB Star Populations in NGC3379 and NGC3384 (M. Gregg) 11:50 - 12:05 The star formation history across the Magellanic Clouds and other Local Group Galaxies (M. Cioni) 12:05 - 14:00 Lunch break 14:00 - 14:35 Population synthesis models and their ingredients (P. Marigo) 14:35 - 14:50 Stellar populations in the Galactic Bulge (E. Vanhollebeke) 14:50 - 15:05 Carbon stars in the bulge - or beyond it? (R. Wahlin) 15:05 - 15:10 SOC announcement: the proceedings 15:10 - 15:45 Coffee break 15:45 - 16:20 Did AGB stars leave their chemical fingerprints in globular clusters? (C. Charbonnel) 16:20 - 16:35 Why Globular Clusters care about AGB stars (R. Gallino) 16:35 - 16:50 Spitzer Observations of Local Group Irregular Galaxies (D. Jackson) 19:00 - 23:00 Conference dinner at the Vienna University Observatory

FRIDAY, 11 August 2006 09:20 - 09:55 AGB stars in extragalactic systems (M. Groenewegen) 09:55 - 10:10 Some clues on the properties of AGB stars from the Surface Brightness Fluctuations method (G. Raimondo) 10:10 - 10:25 AGB stars in Centaurus A group dwarf galaxies (M. Rejkuba) 10:25 - 11:00 Coffee break

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11:00 - 11:15 Infrared molecular bands of AGB stars in nearby galaxies (M. Matsuura) 11:15 - 11:50 PNe as probes of the chemical impact of AGB stars (L. Stanghellini) 11:50 - 12:05 Post-AGB phase of stellar evolution (R. Szczerba) 12:05 - 12:10 LOC announcements 12:10 - 14:00 Lunch break 14:00 - 14:35 The Singular contribution of AGBs to our understanding of galactic dynamics (S. Demers) 14:35 - 14:50 C- and O-miras and the galactic structure (M. Feast) 14:50 - 15:05 The impact of LSST on the AGB research (Z. Ivezic) 15:05 - 15:35 Conference summary (H. Habing)

CONFERENCE INFORMATION Technical Information for Speakers: To minimize ”overhead” during the meeting by switching of laptops we kindly ask you to bring your presentation on a CD or memory stick to copy it onto the computer system of the lecture hall well before your talk. A LOC member will assist you during the coffee breaks and before the morning and the afternoon sessions. If you wish to use an overhead projector please let us know in advance. Name badges: Admission of participants to all sessions is by the conference name badge only. Participants are requested to wear their name badge at all times. Posters: Posters are on display in the foyer of the lecture hall during the whole meeting. Authors are asked to be available at their posters for discussion during the breaks. Each poster board is numbered, numbers are given in this abstract book. LOC members will be around to help you find the location of your poster. Please mount your poster before 10:30 on Monday morning and remove it until 16:00 on Friday.

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SOCIAL PROGRAM

WALKING TOUR ”VIENNA AT FIRST GLANCE” This orientational tour gives you a nice overwiew over the city. Beside the main sight in the city center like the Imperial Palace and St. Stephan’s Cathedral we also dive into more off-the-beaten-track parts of the city with its small streets and hidden courtyards. At every corner there is a part of our 2000 year history to be found starting with the Romans up to modern day life. MONDAY, 18:30-20:30, leaving in front of the campus, optional ending at a restaurant in the city www.viennawalks.com EXCURSION TO THE WACHAU VALLEY ¨ The tour will first lead us to the famous abbey of Melk and afterwards to Durnstein, a charming town at the banks of the River Danube, famous for being the place ¨ where the English King Richard Lionheart was held prisoner. In Durnstein we will also attend a wine tasting before heading back to Vienna. WEDNESDAY, 12:30-20:30, leaving in front of the campus As we will leave immediately after the morning session you can book a packed lunch at the help desk. Please make your bookings before the lunch break on Tuesday. CONFERENCE DINNER The informal dinner will be in the garden of the Vienna Observatory. Guided tours through the observatory and its museum will be offered during the dinner. PLEASE NOTE: Smoking is not allowed in the whole observatory building. ¨ THURSDAY, starting at 19:00, Turkenschanzstrasse 17, 1180 Vienna (see the ”How to get there” section)

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HOW TO GET THERE

From all selected hotels the walking distance to the campus is less than 20 minutes. From Arcotel Boltzmann to the campus: ¨ Take the tram line 5 or 33 from Spitalgasse/Wahringerstrasse heading towards ¨ Westbahnhof or Josefstadter Strasse. Leave at Lange Gasse. From Arcotel Boltzmann to the observatory: ¨ Take the tram line 40 or 41 from Spitalgasse/Wahringerstrasse heading towards ¨ Gersthof or Potzleinsdorf. Leave at Aumannplatz. From Hotel Palais Strudlhof to the campus: ¨ Take the tram line 5 from Spitalgasse/Wahringerstrasse heading towards Westbahnhof. Leave at Lange Gasse. From Hotel Palais Strudlhof to the observatory: ¨ Take the tram line 40 or 41 from Spitalgasse/Wahringerstrasse heading towards ¨ Gersthof or Potzleinsdorf. Leave at Aumannplatz. From Hotel Graf Stadion to the campus: Take tram line 5 or 33 from Laudongasse heading towards Praterstern/Wien Nord or Friedrich-Engels-Platz. Leave at Lange Gasse. OR: Take bus line 13A from Theater in der Josefstadt heading towards Skodagasse. Leave at Skodagasse. From Hotel Graf Stadion to the observatory: Take underground line U2 from Rathaus heading towards Schottenring. Change at Schottentor to tram line 40 or 41 (one level above). Leave at Aumannplatz. OR: Take tram line 33 from Laudongasse heading towards Friedrich-Engels-Platz. ¨ Change into tram line 40 or 41 at Spitalgasse/Wahringerstrasse heading towards ¨ Gersthof or Potzleinsdorf. Leave at Aumannplatz. From Hotel Zipser to the campus: Take tram line 5 from Laudongasse heading towards Praterstern/Wien Nord or Friedrich-Engels-Platz. Leave at Lange Gasse. From Hotel Zipser to the observatory: Take tram line 33 from Laudongasse heading towards Friedrich-Engels-Platz. ¨ Change into tram line 40 or 41 at Spitalgasse/Wahringerstrasse heading towards ¨ Gersthof or Potzleinsdorf. Leave at Aumannplatz. From Porzellaneum to the campus: ¨ Take tram line 5 from Spitalgasse/Wahringerstrasse heading towards Westbahnhof. Leave at Lange Gasse. From Porzellaneum to the observatory:

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¨ Take the tram line 40 or 41 from Spitalgasse/Wahringerstrasse heading towards ¨ Gersthof or Potzleinsdorf. Leave at Aumannplatz. OR: Take bus line 40A from ¨ Bauernfeldplatz heading towards Doblinger Friedhof. Leave at Gregor Mendel Strasse. GENERAL INFORMATION ON PUBLIC TRANSPORT IN VIENNA: Vienna has a quite good and safe public transport system consisting of 5 underground lines and a large number of tram lines and buses. The tram lines and buses typically operate between 6:00 and 23:30, the underground between 5:00 and 0:30. During the night special night buses are running. Tickets for the public transport can be bought in underground stations, at ticket machines, at several newspaper stores and also directly in buses and tramways. A single ticket costs EUR 1.50 (EUR 2.0 if you buy it in the bus or tram). You can use it for one trip in one direction including changes. Tickets bought in advance must be punched in a blue ticket cancelling machine in the tram or bus or at the barrier before you board the underground train. There is also a one week ticket (Monday to Sunday) for EUR 12.50. Another alternative is a 8-day ticket for EUR 24. You can use it at any 8, not necessarily consecutive days. The advantage of this ticket is you can use it for several people travelling together: simply punch one strip for each person in the group. Children under the age of six travel free of charge, between 6 and 15 they have to pay the half price. If you have any questions please contact the helpdesk. EMERGENCY INFORMATION: Emergency numbers: Fire brigade 122, medical emergency 144, police 133 Pharmacy: Tiger Apotheke, Alser Strasse 12 Helpdesk: +43 650 5106910 LOC members: +43 650 7285666 (Lebzelter), +43 664 4561316 (Hron), +43 664 8175060 (Kerschbaum) OTHER PRACTICAL INFORMATION: Cell phones: You are kindly requested to have your cell phone turned off while in any of the conference sessions. Thank you for your co-operation. Internet connection: There is a WLAN access in the foyer of the lecture hall. A further internet access will be provided in a nearby terminal room. Details will be given at the meeting. Parking: There is no possibility to park your car inside the campus. Around the campus there are only short term parking areas (maximum allowed time 2 hours) and you require a parking ticket. We recommend to leave your car at the hotel and use the public transport or walk. Usually you find some parking space close to the observatory free of charge. Smoking is not permitted inside in the campus buildings or the observatory building. Taxi: call 40100 or 60160

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HUNGRY? This is a non-complete list of nearby places to eat: Inside the campus (Austrian type): Bierheuriger Zum Gangl: Hof 1 Salettl: Hof 1 Stiegl-Ambulanz: Hof 1 ¨ Hof 1 Uni-Brau: Outside the campus: Adam: Austrian; Florianigasse 2 ¨ Cafe Weimar: Austrian; Wahringer Strasse 68 ¨ McDonald’s: Fast Food; Josefstadter Strasse 73 Pizzeria Guiliano: Italian; Tendlergasse 3 Rembetiko: Greek; Porzellangasse 38 Safran: Indian; Garnisongasse 10 Stadtheuriger - Zum narrischen Kastanienbaum: Austrian; Strozzigasse 36 Tokyo Running Sushi: Japanese; Laudongasse 34 Tunnel: cheap student restaurant; Florianigasse 39

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Map of the University campus.

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Campus and surroundings.

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Location of the Observatory.

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Overview.

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Oral Presentations

AGB stars in stellar evolution models: concepts and problems Lattanzio, John I will first provide a quick summary of AGB star structure, evolution and nucleosynthesis for orientation. Then I will concentrate on the main uncertainties, and where we can and cannot expect to make much progress in the coming years.

The evolution of super-AGB stars Siess, Lionel Stars in the mass range 7-11 M exhibit a very peculiar structural evolution characterized by off-center C ignition followed by the propagation of a deflagration carbon burning front to the center. Then, if the newly-formed NeO core is not too massive, the star develops thermal pulses and enters the so-called super-AGB phase. In light of new stellar models, we review these evolutionary features focusing on the super-AGB phase. In particular, we discuss the nucleosynthesis associated with this stellar population.

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Towards simulating the photometry, chemistry, mass loss and pulsational properties of AGB star populations in resolved galaxies. Girardi, Leo The latest TP-AGB tracks from Marigo have been implemented in the TRILEGAL population synthesis code, which simulates photometric catalogs for any galaxy given its total mass, distance, star formation history and age-metallicity relation, and including also the Milky Way foreground population. Among the basic stellar parameters to be simulated, we now include the surface chemistry (C/O ratio), mass-loss rates, pulsation modes and periods. This allows us to perform a series of consistency checks between the predictions of AGB models and observations, that we are just starting to explore. We present a few examples of model-data comparisons, regarding mostly the near-infrared photometry and variability data for AGB stars in the Magellanic Clouds.

Inside AGB stars: elemental synthesis Busso, Maurizio I review the status of nucleosynthesis studies in AGB stars, with emphasis on the existing, possible or needed observational tests. Nuclear processes of relevance in this context are those occurring in H- and He-burning layers, below the huge convective envelope and above the degenerate C-O core, while the star undergoes thermal instabilities from the He-shell (the thermal pulses) and appears from the outside as a long-period variable of the Semi-regular of Mira type. The crucial nucleosynthesis products include p-capture isotopes from the warm cycles of H-burning (covering the atomic mass region from Carbon to Magnesiuum) and the neutroncapture products generally known as s-process nuclei, extending up tp lead and bismuth. The nature of the basic nuclear reactions active in these stages is varied, including primary-like and secondary-like processes, so that the resulting pattern of abundances has a strong and complex dependence on metallicity. I review the interplay of models and observations on these issues from the early stars in the galactic halo to the high-metallicity AGBs of the galactic disk. I also underline how other constraints, coming from meteoritic sciences and gamma-ray line astronomy have recently integrated the information coming from stellar spectroscopy. Finally, I briefly mention how open problems on AGB physics (mass loss, mixing mehcanisms) affect the predictions of the AGB chemical yelds.

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Light s-process element production in solar metallicity AGB Stars Karakas, Amanda Low and intermediate-mass Asymptotic Giant Branch stars are the dominant production site for many of the slow-neutron capture elements in the Galaxy. We compute a series of solar metallicity (Z = 0.012) AGB structure models of 1.5, 3 and 5 solar masses and follow the evolution from the main sequence to near the end of the thermally-pulsing AGB phase. We include a partial mixing zone of constant mass at the deepest extent of each dredge-up episode in the 1.5 and 3 solar mass models. This mixing zone produces a 13 C pocket in the top ∼1/10th of the He-rich intershell, facilitating the production of heavy s-process elements. Using a post-processing code that includes 156 species, 1260 reaction rates and time-dependent convective mixing we follow the nucleosynthesis of all stable isotopes up to arsenic-75 although future work will involve extending this network to the first s-process peak. We present the results of our computations and compare with Gallino et al. (1998) and observations of planetary nebulae.

Convective and non-convective mixing in AGB stars Herwig, Falk I will review the properties of rotating AGB stellar models, who at the current state do not reproduce observed properties of AGB stars and their white dwarf progeny. I will briefly talk about other non-standard mixing. Then I will talk about convective mixing, focusing on new results from hydrodynamic He-shell flash convection. New simulations deal with the ingestion of H into He-shell flash, that occurs in a significant fraction of pre-white dwarf post-AGB stars and maybe in extremely metal poor AGB stars.

The impact of rotation on the nucleosynthesis in metal-poor AGB stars Decressin, Thibaut We study the effects of meridional circulation and shear turbulence on the structure and evolution of metal-poor stars with masses between 2.5 and 7Msun all along their life. Stellar models are computed from the pre-main sequence up to the end of the TP-AGB phase including the most recent theoretical developments regarding rotation-induced mixing. We discuss in details some specific features such as the evolution of the surface composition and the total chemical yields.

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Atmospheres of AGB Stars: status and challenges of modelling Gustafsson, Bengt The REAL AGB star atmospheres are most probably far from any present models, as regards fundamental principles as well as physical details. How can the models be realistically improved – and does it matter and does it help? Some suggestions for further efforts, as well as some warnings, will be presented.

Laboratory data for cool star modelling Bernath, Peter The laboratory data needs for the simulation of the spectral energy distributions emitted by cool stars and brown dwarfs will be reviewed. The current status of molecular line parameters needed to compute the required molecular opacities will be discussed. Examples of recent progress in this area will be provided for water, metal hydrides and other molecular species.

Spitzer/IRAC Characterization of Galactic AGB Stars Marengo, Massimo The Spitzer Space telescope, and in particular its InfraRed Array Camera (IRAC) is an ideal facility to study the distribution of AGB stars in our own and other galaxies because of its proficiency in surveying vast areas of the sky in a short time, and its ability to detect sources with infrared excess. The IRAC colors of AGB stars, however, are not well known, due to numerous molecular absorption features in the spectral region covered by the IRAC photometric system. The presence and strength of these features depends on the chemistry of the stellar atmosphere, the mass loss rate and can change with time due to the star long period variability. To characterize the colors of AGB stars in IRAC bands we proposed a Spitzer Guaranteed Time Observation program to observe a large sample of AGB stars with IRAC. The results will be made available to the community in the form of template magnitudes and colors for each target, with the goal of aiding the identification of AGB stars in already available and future IRAC surveys.

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The period-luminosity relation of Mira variables in globular clusters Matsunaga, Noriyuki & the IRSF/SIRIUS team We report a result of our near-infrared repeated observations of Mira variables in globular clusters, pulsating stars at the last stage of low-mass AGB stars. We will discuss their period-luminosity relation and the application as a distance indicator. By obtaining the distances to globular clusters with some methods independent from Mira variables, we obtained the clear period-luminosity relation. The root mean square residual is no larger than that for Mira variables in the Large Magellanic Cloud. We will derive distances to some clusters whose distances were highly uncertain, for example, due to high extinction. Especially, we will focus on NGC 6388 and NGC 6441, peculiar globular clusters with RR Lyr variables in spite of their high metallicity. Their period distribution is similar to that of metal-poor Oosterhoff-II clusters, but recent spectroscopic measurements show they have higher abundance ([Fe/H]∼−0.7, Clementini et al. 2005). We discovered some new Mira variables in these clusters, and can derive their distances from Mira variables for the first time. The obtained distances revealed that the absolute magnitude of RR Lyr variables in these clusters are similar to the metal-poor ones of [Fe/H]=−2. Our results strengthens the peculiarity of the two clusters.

Recognition and Classification of AGB Stars by Narrow-Band TiO/CN Photometry Wing, Robert F. The molecules TiO and CN both have extensive band systems throughout the near infrared regions where AGB stars are brightest. For the recognition of C stars and M stars later than about M3, a simple index defined by a pair of interference filters will suffice, and many Local Group galaxies have been surveyed in this way. However in stars of types K4 to M2 or so, both TiO and CN are present, and at comparable strengths, so that the two-filter index is not useful. Both molecules can be measured by adding a nearby continuum filter - or better, a pair of continuum filters which also measures the star’s color. It is useful to measure both molecules separately because they provide different information in oxygen-rich stars, TiO being sensitive to temperature and CN to luminosity. The optimum placement of filters for the twodimensional (TiO/CN) classification of K and M stars, and for the recognition of other types including carbon stars, S stars, and M dwarfs, is discussed.

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Theoretical AGB and post-AGB Stellar Models for Synthetic Population Studies Kitsikis, Agis & Weiss, A. I will present new AGB and post-AGB tracks computed with the latest version of the Garching stellar evolution code. The intermediate-mass star calculations use the OPAL equation of state and opacity tables, new molecular opacities and reaction rates, and up-to-date mass loss prescriptions – van Loon et al. (2005), Wachter et al. (2002) – for the AGB’s superwind phase. Tracks for different metallicities evolving from the MS to the WD phase have been computed. One of the cases considered is a supersolar metallicity with relative enhancement of alpha-elements in order to best represent elliptical galaxies. The scientific motivation for this project is to replace the commonly used old tracks of Vassiliadis & Wood (1993) that provide an input for the Marigo et al.(2004) synthetic population models in order to try and theoretically understand the Planetary Nebulae Luminosity Function. Since it’s bright cut-off invariance property is not reproduced by the synthetic populations for elliptical galaxies with a predominantly old population, these tracks are a first step towards further investigation.

Measuring abundances on the AGB Smith, Verne

AGB Stars in Globular Clusters Lebzelter, Thomas, Hinkle, K.H., Lederer, M., Posch, T., Wood, P.R. In several globular clusters we find a sufficiently large sample of AGB stars with a well defined mass, metallicity and luminosity to study various properties of AGB stars. Knowledge of these basic parameters is essential for comparing observations with stellar pulsation and mixing models. Here we will present two main results from our work in this field of the past three years. From high and medium resolution near infrared spectra we show the occurrence and evolution of dredge up along the AGB in globular clusters of various mass. Abundances of C and its isotopes are determined from state of the art atmospheric models. Second we will report on using pulsation properties as an independent indicator for mass loss. For this we obtained long photometric time series of various globular clusters to detect new AGB variables and determine their period.

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Determination of element abundances Hauschildt, Peter

Modelling Mass Loss: Dynamics, Dust, Drama ¨ Hofner, Susanne Mass loss is one of the most crucial features of AGB stars, influencing both their evolution and their observable properties in a decisive way. The phenomenon is caused by an intricate interplay of atmospheric shock waves created by pulsation, a strong radiation field, and non-equilibrium dust formation, presenting a considerable challenge to self-consistent modelling. Nevertheless it is clear that realistic models predicting mass loss rates and synthetic spectra are crucial for our understanding of this phase of stellar evolution. While a number of important questions are still open, significant progress has been achieved during the past decade, and selfconsistent models of atmospheres and winds of AGB stars are reaching a stage where a quantitative comparison with observations becomes possible. I will give an overview of the present status of dynamical wind models and discuss both current trends and persisting problems in this field.

What drives the mass loss of oxygen-rich AGB stars? Woitke, Peter It is commonly accepted that the massive winds of AGB stars are driven by radiation pressure on dust which forms occasionally behind shock waves created by the stellar pulsation. However, the problem of dust formation in oxygen-rich gases is complicated. Many solid phases can condense simultaneously on the first seed particles, resulting in dirty grains. Most pure condensates like Al2 O3 , Mg2 SiO4 , etc. have glassy opacities, i.e. they are almost transparent in the optical and near IR spectral region where the star releases most of its energy. Consequently, these condensates can exist astonishingly close to the star, but they are not effective in driving an outflow. Solid iron or iron-contaminated dust particles seem to play a key role for the understanding of the winds of oxygen-rich AGB stars. In this talk, I will report on 2D hydrodynamical models with time-dependent dust formation theory and coupled frequency-dependent Monte-Carlo radiative transfer. I will comment on dynamical instabilities unrevealed by previous 1D models, and on first results concerning the oxygen-rich case.

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The dust sequence along the AGB Blommaert, Joris, Vanhollebeke, E., Cami, J., Groenewegen, M., Habing, H., Kemper, C., Omont, A., Schultheis, M., Tielens, X., Waters, R., Wood, P. With Spitzer-IRS we observed a homogeneous sample of Oxygen-rich AGB stars in the Galactic Bulge. The Spitzer-IRS wavelength range 5.2−38 micron contains the major spectral features of aluminium oxides, spinel, magnesium-iron oxides as well as those of amorphous and various crystalline silicates. Previous studies have shown these components to be abundant in AGB environments, albeit with highly varying relative abundances. The stars in our sample all originate from about 1.5 solar mass stars, and only differ in their ages along the AGB. Moreover, this sample fully covers the range in AGB mass-loss rates, from the onset of mass loss on the AGB up to the superwind phase. We can therefore link for the first time the spectral differences in dust composition directly to the age on the AGB. Our observations provide a unique observational baseline for studies of dust evolution in AGB stars in our own and other galaxies.

Dust formation and growth Andersen, Anja C. Mass-loss and dust formation accompany the late evolutionary phase of several stellar types. In AGB stars part of the heavy elements present in the star - at formation as well as part of the freshly synthesized elements - is returned into the interstellar medium as tiny solid dust particles. In the pulsating atmospheres of AGB stars the condensation of dust grains is strongly connected with the shock wave structure of the circumstellar envelope, usually triggered by a two step mechanism. First there is nucleation of critical clusters from molecules and this is followed by growth to macroscopic dust grains. Grain growth will usually proceed far from equilibrium. The formation of dust particle in AGB stars alters the atmospheric structure and thereby influence the local and global circumstellar envelope dynamics and the detailed time-dependent spectral appearance of the star. The spectral appearance is strongly influenced by the material properties of the dust particles formed.

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Molecular clusters in dust nucleation processes in circumstellar outflows of oxygen-rich AGB stars Patzer, Beate The transition from a circumstellar gas into dust particles takes place via the formation and growth of small molecular clusters in the gas phase. In many cases the required kinetic and thermodynamic data of such microphysical processes are rarely available. Therefore, the physical properties of molecular clusters possibly involved in dust formation processes from the gas phase have been investigated theoretically employing computational electronic structure techniques. The properties, thus obtained, are necessary prerequisites for the study of such phase transitions in astrophysical environments such as the circumstellar surroundings of cool, late-type stars on the AGB. New results regarding the nucleation of dust particles in circumstellar outflows of oxygen-rich AGB stars are presented.

Observations of water-ice in OH/IR stars Justtanont, Kay We observed a total of 17 OH/IR stars in the near-IR to search for the presence of water-ice band using Stockholm InfraRed CAmera (SIRCA) plus an addition 6 stars from previous data from UKIRT CGS4. We have enlarged the number of known stars with water-ice. We derived the mass loss rate of individual star and were able to confirm earlier relationship between mass loss rate and water-ice column density. Surprisingly, not all stars show the water-ice absorption band. We investigated different scenarios to explain the phenomenon. There is evidence that these stars have undergone the superwind phase within the past 1000 years.

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The composition of dust surrounding AGB stars Waters, Rens The outflows of Asymptotic Giant Branch (AGB) stars are characterized by the condensation of small dust particles, that are believed to be an important ingredient in driving their winds. The nature of the dust that condenses depends on local conditions in the dust formation region, such as chemical composition, temperature and density. AGB stars are the main contributor of stardust to the interstellar medium. On a galactic scale, it is therefore important to understand these sources of interstellar dust. Infrared spectroscopy of AGB winds and comparison of astronomical data to laboratory spectra of cosmic dust analogues is a powerful way to determine the nature of AGB dust.

Spitzer/MIPS Infrared Imaging of the Extremely Extended Circumstellar Dust Shells around Speck, Angela Asymptotic giant branch (AGB) stars suffer mass loss which leads to the formation of a circumstellar shell of gas and dust. However, the mechanisms by which they do this are not well understood. A fossil record of AGB mass-loss should be preserved in the circumstellar shells of such stars. The MIRIAD team has a Spitzer/MIPS program to observe the extended dust emission around several AGB and post-AGB stars. We present results from these observation and compare to previous FIR observations of several (post-)AGB stars including (but not limited to) HD 161796, AFGL 2688 and R Hya. From our high sensitivity/resolution observations we determine the radial density distribution in the circumstellar shells and thus the mass-loss histories of these stars. Recent studies have suggested that there are radial density enhancements in the circumstellar shells of post-AGB stars. We determine the veracity of this claim, and calculate the timescales for episodic mass-loss changes based on the density structures of the dust shells. Furthermore, since our sample stars represent a range of (known) elemental abundances, we compare the derived mass-loss histories to determine the difference due chemistry. In addition, we compare the derived dust density distributions with those predicted using stellar evolution/hydrodynamical models. From this study we will be able to (a) constrain the mass of the progenitor star; (b) test theories of stellar evolution and mass-loss mechanisms; (c) determine the effect of dust chemistry on mass loss (and therefore on stellar evolution).

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VLTI - present and future prospects Richichi, Andrea

Study of the circumstellar envelopes of AGB and early post-AGB stars Castro-Carrizo, Arancha, Quintana-Lacaci G, Alcolea J., Bujarrabal, V. Grewing, M., Lindqvist, M., Lucas, R., Neri, R., Olofsson, H., Schoier, F.L., Winters J.M. A systematic study of circumstellar envelopes (CSEs) of evolved stars is being carried out with the IRAM Plateau de Bure interferometer and the Pico de Veleta 30m telescope. We are mapping with resolutions down to 1” the 12 CO J=1-0 (115GHz) and 2-1 (230GHz) emission in 37 AGB and 9 early post-AGB stars, selected to represent the large variety in chemistry, variability types, etc., of these objects. With radiative transfer models we are determining the main properties of their CSEs, their mass-loss history and geometry, velocity field, degree of clumpiness, photodissociation radius, etc. From first results we find a large diversity of characteristics. The (approximate) circular symmetry and smoothness observed in the brightness distribution of some CSEs (e.g. V Cyg), contrast with the various axisymmetric distributions observed in other sources (e.g. RX Boo, IRAS21282+5050 and V Hya), in their very inner CSE regions and/or in their overall envelopes. Additionally, CO mappings in the yellow hypergiants IRC+10420 and AFGL2343 show exceptional massive CSEs expanding at high velocity, each one presenting variations in the mass-loss rate and remarkable anisotropies.

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Submm CO line observation and modelling from circumstellar envelopes Teyssier, David We present the results of a multi-transition CO observational program conducted on a sample of AGB and post-AGB stars envelopes. We have collected maps and single pointing observations of these envelopes in 5 rotational transitions ranging from J=1-0 to J=6-5. Using a model for the CO emission of an AGB circumstellar envelope, in combination with a standard LVG approach, we have conducted a systematic modelling analysis using the whole set of CO data collected for a sample of 12 sources. We simultaneously fit all five transitions, taking into account the spatial information provided by the maps. We find mass-loss rates in the range 10−7 to 4x10−4 solar masses per year, and envelope temperatures ranging from 20K to 1000K at a radius of 1016 cm. We show that most AGB data can be fitted using a constant mass loss rate, at least within the calibration uncertainties associated with the data collected at different frequencies. For some cases though (e.g. CIT6, R Hya, chi Cyg), a change in the mass loss rate history needs to be invoked to reconcile data at low- and high-J, a scenario already mentioned by several authors.

What do we really know about AGB mass loss? Willson, Lee Anne What do we really know about mass loss and core mass for AGB stars? 1. Mass loss rates are very sensitive to stellar (and modeling) parameters; most empirical relations are mainly the result of this fact combined with strong selection effects. 2. Mass loss removes the envelope in about 200,000 years. 3. The stellar parameters where this mass loss occurs are well constrained, while the mass loss rate for a given set of stellar parameters is not well constrained. 4. At least 2 mechanisms are involved in driving mass loss - waves, dust - and both probably require pulsation to be effective in removing mass. 5. The core masses are smaller at a given L than traditional L-Mc relations suggest. While important details remain to be worked out, we can be confident that the AGB ”death line” is known for populations currently available for study, and a good first order estimate is available for other populations (such as young, low-Z). This is good news for population modeling. However, one major uncertainty remains: The amount of mass lost at/near the tip of the RGB. I will review the observational and theoretical evidence that supports the above conclusions.

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Methods for determining AGB mass loss rates based on radio data ¨ Schoier, Fredrik Mass loss is the single most important process during the final evolution of low- and intermediate-mass stars on AGB. Its existence is well established, but much of its finer details is essentially unknown. This is unfortunate since even a modest mass loss rate change by a factor of two will have a profound effect on the evolution of the star, its nucleosynthesis, and its mass return to the interstellar medium. Presented here is a review of various methods fo estimating mass loss rates based on molecular line observations. Special attentionwill be given to CO radio line emission which has been considered, when supplemented by detailed radiative transfer modelling, as a very (perhaps the most) reliable AGB mass loss rate estimator. Presented here are extensive studies of the mass loss properties of a sample of some 180 AGB stars (including carbon stars, S-stars and M-type AGB stars).The sample is dominated by low mass loss rate objects, and it is concluded that for this type of objects the CO radioline emission is a good mass loss rate estimator, although not entirely free of problems. The uncertainties involved in the modelling procedure will be discussed.

Methods for determining AGB mass loss rates based on optical and infrared data van Loon, Jacco I review the methods that use optical and infrared data to yield mass-loss rates of red giant stars. These are based either on the extinction, scattering and re-emission of the stellar radiation by circumstellar dust grains, or on the excitation of atomic electronic or molecular vibration-rotation transitions. I describe the application of each method, and discuss the assumptions that are made and the implications for our knowledge and understanding of the mass loss from red giant stars.

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On the Connection between Mass Loss and Evolution of Carbon-rich AGB Stars. ¨ Mattsson, Lars, Hofner, S., Herwig, F. The mass loss properties of carbon (AGB) stars are not very well constrained at present.A variety of empirical or theoretical formulae with different parameterisations are available in the literature and the agreement between them is anything but good. These simple mass loss prescriptions are nontheless used in many models of stellar evolution without much consideration of their applicability in various cases. We present here an on-going project aiming at a better description of the mass loss, that could be used to improve stellar evolution models – especially the evolution during the TP-AGB phase. As a first step, we have considered the mass loss evolution during a He-shell flash. Using stellar parameters sampled from a stellar evolutionary track, we have computed the time evolution of the atmospheric layers and wind acceleration region during a flash event with detailed frequency-dependent radiation hydrodynamical models including dust formation. Based on these results, we have also simulated the subsequent long-term dynamical evolution of the circumstellar envelope (CSE), including the formation of adetached shell. We find that existing simple mass loss prescriptions imply different mass loss evolutions compared with our model. The second step of the project deals with the dependence of mass loss on the basic stellar parameters. We are at the moment computing a large grid of wind models for C-rich AGB stars, that in the future is supposed to be extended with models of O-rich AGB stars. Preliminary results show that simple parameterisations are difficult to obtain in certain regions of the parameter space considered.

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On Luminosity and Mass Loss of Galactic AGB Stars Guandalini, Roald As a part of a reanalysis of galactic AGB stars at infrared wavelengths, we discuss here 2 samples (the first of carbon-rich stars, the second of S stars) for which photometry in the near- and mid-IR and distance estimates exist. Whenever possible we searched also for mass loss rates. Spectral energy distributions were always up to 20 µm and for the best observed sources up to 45 µm. The sample of S stars was searched for spectroscopic observations of Tc in the literature. The wide wavelength coverage allows us to obtain reliable bolometric corrections, hence magnitudes. We show that mid-IR fluxes are crucial to estimate the magnitudes of stars with dusty envelopes. We construct HR diagrams and in particular show that the so-called luminosity problem of C stars (i.e. the suggested fact that they would be less luminous than predicted by models) does not appear to exist. We examine the different properties of these stars according to their type of variability and show that the statistical relevance of Miras and Semiregulars varies with evolution, with Miras dominating the final stages. For both samples we show the relations between different physical parameters like mass loss rates, bolometric magnitudes, infrared colors and variability period with the aim of finding evolutionary costraint. In particular, the evolutionary status of various classes of C and S stars is discussed.

Quantitative results on AGB mass loss rates Wood, Peter The final evolution of AGB stars is dominated by mass loss, which determines the masses of remnant white dwarfs, masses of planetary nebulae, and enrichment of the interstellar medium in elements such as carbon, nitrogen and s-process elements. I will briefly discuss past estimates of the mass loss rate from AGB stars, then present new estimates of mass loss rates from Magellanic Cloud stars which have been derived from Spitzer space telescope data. I will give the background to the Spitzer observations and estimate how the observed mass loss rates can be related back to intrinsic stellar properties.

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Polychromatic interferometry of evolved stars with VLTI and VLBA Wittkowski, Markus We report on our project to study the atmospheric structure and the circumstellar environment of evolved stars using optical and radio long-baseline interferometry. VLTI observations of the cool giants psi Phe, gam Sge, and alf Cet were used to calibrate stellar model atmospheres of regular non-pulsating cool giants as well as to derive high-precision fundamental parameters. VLTI observations of the Mira variable R Leo are consistent with self-excited dynamic Mira model atmospheres that include molecular shells close to continuum-forming layers. Coordinated observations at near-infrared, mid-infrared,and radio wavelengths of evolved stars were conducted, aiming at a better understanding of the stellar pulsation, the mass-loss process, and the triggering and formation of asymmetric structures. Results from our pilot study on the Mira variable S Ori show that the SiO maser reside at a distance of about 2 photospheric radii, a result that is consistent with model estimates and other observations, and that is virtually free of the usual uncertainty inherent in comparing observations of variable stars often widely separated in time.

Mass-loss rates of AGB stars in Sagittarius and Fornax Dwarf Spheroidal Galaxies Lagadec, Eric The effect of metallicity on the mass-loss rate of AGB stars is not well known.Theory suggests a weakening of mass-loss rate with metallicity, as fewer grains will be formed, diminishing the dust-driven wind.However, observations made in the Small and the Large Magellanic Clouds (SMC and LMC) indicate little evidence of diminution of mass-loss rate in these galaxies with low metallicities with respect to the Milky Way ([Fe/H]=-0.73 and -0.30 for the SMC and LMC respectively). To further study this problem, we have conducted mid-infrared photometric measurements of AGB stars in the Sagittarius and Fornax Dwarf Spheroidal Galaxies ([Fe/H]=-1.1 and -1.3) with the 10-micron camera of VISIR at the VLT. These observations combined with previous near-infrared photometric measurements allow us to estimate mass-loss rates in these galaxies. We will present these new results.

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Chemodynamical models of galaxy evolution Tosi, Monica AGB stars and their progeny, PNe, are important contributors to the chemical evolution of galaxies. They are also excellent tracers of intermediate-age populations in resolved external galaxies, thus providing fundamental information on their star formation histories and evolutions. In this review, I will summarize some of the aspects of chemodynamical evolution modelling related to AGB stars, for our own Galaxy and for a few late-type dwarf galaxies.

Yields from AGB stars and their impact on the chemical evolution of dwarf galaxies Recchi, Simone By means of 2-D hydrodynamical simulations coupled with detailed chemical yields originating from SNeII, SNeIa and intermediate-mass stars, we study the dynamical and chemical evolution of dwarf galaxies with structural parameters similar to NGC1569 and IZw18. It is shown that bursts of star formation with short durations are not able to account for the chemical properties of these galaxies. The best way to reproduce them is to assume long episodes of star formation separated by short quiescent periods (gasping star formation). Different sets of yields from intermediate-mass stars are tested, in order to discover which one better reproduces the chemical composition of these two galaxies (in particular for what concerns nitrogen). Moreover it is shown that, if the star formation is bursting, a fast cooling of the freshly produced metals is expected, whereas in case of gasping star formation the metals released by the last episodes of star formation are either channelled along the galactic wind or are in a too hot phase to contribute to the chemical enrichment of the galaxy.

AGB Stars & Starbursts Gallagher III, John S. Star formation in starbursts often is concentrated in dense clusters which in turn are embedded in scaled OB associations which make up starburst clumps. These conditions raise interesting problems for the evolution of AGB stars, especially for those located within super star clusters. The implications of such close packing of AGB stars will be briefly considered and compared with observed porperties of aging super star clusters in nearby starbursts.

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Star formation history as probed by AGB stars Grebel, Eva E-AGB stars are luminous tracers of intermediate-age populations that can easily be detected and resolved with 8-10m class telescopes in nearby galaxies well beyond the Local Group. Even at the distance of M31 these stars already play an important role as indicators of the presence of an intermediate-age population and its approximate properties. Special filter systems or spectroscopy permit us to distinguish subtypes such as C and M stars and to measure their numbers and ratios. In turn, this provides information about the duration and intensity of star formation a few hundred million to several billion years in the past, imposing valuable constraints on galaxy evolution in different galaxy types and environments.

AGB Star Populations in NGC3379 and NGC3384 Gregg, Michael, Ferguson, H., Minniti, D., Tanvir, N. Using Hubble NICMOS and ACS imaging, we have resolved the AGB and RGB populations of two nearby early type galaxies in the Leo Group, NGC3379 (E0) and NGC3384 (S0). The resulting color-magnitude diagrams are being used to characterize their ages and metallicities, constraining their relative star formation histories and evolution. The results set firm benchmarks for modeling the integrated spectral light of more distant galaxies, and the comparison of the two objects provides insight into the origin of S0 galaxies.

The star formation history across the Magellanic Clouds and other Local Group Galaxies Cioni, Maria-Rosa The Ks magnitude distribution of AGB stars, interpreted using up-to-date stellar evolutionary models, provides important constraints on the spatial variation of metallicity and mean age of the underlying stellar population of galaxies. I will present the result of this study across the Magellanic Clouds, M33, NGC 6822 e SagDIG and I will discuss the tremendous improvement that new wide-field infrared instruments (i.e. VISTA) will provide on our understanding of the global intrinsic as well as dynamical history of these systems.

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Population synthesis models and their ingredients Marigo, Paola A review will be given on the importance of population synthesis models of galaxies including AGB stars. Basing on the existing literature, the presentation will discuss first different theoretical techniques to simulate synthetic AGB stellar populations, and then it will illustrate a few of the most interesting applications. Final remarks will be made on possible future prospects.

Stellar populations in the Galactic Bulge Vanhollebeke, Evelien, Groenewegen, M., Girardi, L. There is still quite some debate about the characteristics of the Galactic Bulge. Does the Galactic Bulge consist mainly of an old population of about 10 Gyr (Zoccali et al. 2003) or is there, based on a study of Mira variables, also an intermediate age population of a few giga years (Groenewegen and Blommaert 2005) or maybe even a young population of 200 Myr (Van Loon et al. 2003)? How do we fit in the bar, has it an viewing angle of 20deg (Binney et al. 1997) or is it more something like 45deg (Groenewegen and Blommaert 2005). What is the distance to the Galactic Centre? 8.0 kpc or maybe 9.0 kpc? With the use of TRILEGAL (Girardi et al. 2005) we constructed a grid of models trying to explain observations of the Galactic Bulge. These models are used to construct color magnitude diagrams (CMD) which are then compared to the observed CMD from 2MASS and OGLE. We will present preliminary results.

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Carbon stars in the bulge - or beyond it? Wahlin, Rurik We will present abundances of carbon and oxygen for a sample of carbon stars in the Sagittarius dwarf galaxy including its stream and towards the galactic bulge. The carbon stars in the bulge was recently proposed to belong to the Sagittarius system which with its lower metallicity more easily would produce carbon stars (Ng 19971999). It is not obvious that this is the case, but the overall metallicities in the dwarf and bulge systems are expected to be different and the abundances might be used to distinguish between true members of the bulge and members of the Sagittarius stream seen through the bulge. The abundances are determined from infrared spectra obtained with the ISAAC spectrometer on VLT (R=1500). The synthetic spectra used in the analysis are computed with the MARCS model atmosphere code, originally presented in Gustafsson et al. (1975).

Did AGB stars leave their fingerprints in globular clusters? Charbonnel, Corinne It has been known for more than two decades that globular cluster stars exhibit chemical abundance anomalies which are not shared by their field counterparts. Two main scenarii have been proposed in the past to explain these differences : The primordial (or pollution) scenario and the evolutionary (or intrinsic) one. Recent spectroscopic observations on very large telescopes have raised the weight of the primordial solution. However the stellar sources responsible for these abundance variations have not yet been indubitably identified. It is often claimed that AGB stars may well be the culprits. In this talk we review the recent custom-made models which were computed in order to quantitatively test this hypothesis. We also discuss the constraints on the IMF of the galactic globular clusters.

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Why globular clusters care about AGB stars Gallino, Roberto, Bisterzo, S., Ivans, I.I., Yong, D. The photospheric abundances of stars in globular clusters have been the subject of heated debate. The observed abundances may be the signature of deep internal mixing in giant stars and/or evidence of pollution by stellar winds by low- to intermediate-mass AGB stars. We suggest that both phenomena may be required in order to understand the peculiar abundances and star-to-star scatter variations by light elements, C, N, O, F, Na, Mg, Al in globular cluster giant stars. Enrichment of sprocess elements such as Ba, La, have been observed in M4, and recently in Rb, Y, Zr and Pb. Analyses of Mg isotopes and of heavy elements abundances have been performed in NGC6752, M13, M71. General contraints and predictions from detailed nucleosynthetic AGB models of different mass and metallicity are discussed. The special case of Omega Cen is briefly revisited.

Spitzer Observations of Local Group Irregular Galaxies Jackson, Dale, Skillman, E.D., Gehrz, R.D., Polomski, E., Woodward, C.E. We present Spitzer/IRAC near-infrared imaging of the Local Group irregular galaxies IC 1613, Sextans A, and WLM. These observations provide a nearly complete census of the asymptotic giant branch stars in these galaxies. By matching these data with optical photometry we are able to measure what fraction of the AGB population are undetected or mis-identified in the optical data due to reddening effects. We also compare our infrared fluxes with AGB star models to estimate wind optical depths and mass-loss rates.

AGB stars in extragalactic systems Groenewegen, Martin I will be reviewing the methods to identify AGB stars in extragalactic systems, and will present a census AGB stars in the Local Group. With space-based and 8m class ground-based telescopes it is now possible to study in some detail the nearby extragalctic AGB stars and I will present some results on the mass-loss rates in carbon stars in the Magellanic Clouds obtained with Spitzer IRS, and on NIR spectroscopy on AGB stars in the Fornax dSph.

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Some clues on the properties of AGB stars from the Surface Brightness Fluctuations method Raimondo, Gabriella The Surface Brightness Fluctuation (SBF) method has been recently recognized to be effective for tracing the stellar content in distant galaxies. We present theoretical results concerning the reliability and efficiency of SBF in evaluating the properties of AGB stars in unresolved stellar populations.

AGB stars in Centaurus A group dwarf galaxies Rejkuba, Marina I will present the deep J and K-band photometry for 14 Centaurus A group dwarf galaxies. The near-IR photometry of individual red giant stars in these galaxies obtained from ISAAC images is supplemented with optical data from archival HST images for 4 galaxies. Deep near-IR color-magnitude diagrams and optical-nearIR color-color diagrams are used to analyse the stellar populations on the upper red giant branches of these galaxies. The fraction of the intermediate-age AGB population is estimated from the number of stars located above the tip of the red giant branch.

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Infrared molecular bands of AGB stars in nearby galaxies Matsuura, Mikako Recent near- and mid-infrared spectroscopic observations of AGB stars in the nearby galaxies reveal the effects of the metallicities on the molecular abundances. We have obtained spectra from 3 to 38 microns using the Very Large Telescope and the Spitzer Space Telescope. Spectra in this wavelength range cover various molecular bands, such as HCN, C2 H2 , CO, and C3 for carbon-rich stars, and SiO, H2 O and CO for oxygen-rich stars. Among carbon-rich stars, the equivalent widths of HCN reduce towards stars in the Large Magellanic Cloud (LMC: about half of the solar metallicity) and the Small Magellanic Cloud (SMC: about quarter of the solar metallicity), as the nitrogen abundance is less at low metallicity. On the other hand, the C2 H2 abundance increases at low metallicity, because carbon atoms are synthesized in AGB stars, which enhances the carbon-to-oxygen ratio at low metallicity. Thus, for carbon-rich stars, this study predicts more carbon-bearing molecules, and also carbonaceous dust despite the low metallicity. Among oxygen-rich stars, there is less SiO in the LMC, due to the low metallicity effects, suggesting less silicate dust grains at a low metallicity environment.

PNe as probes of the chemical impact of AGB stars Stanghellini, Letizia Planetary nebulae (PNe) represent the final stage of AGB stars, and they are ideally suited to probe the chemical evolution of the Milky Way and beyond, since elemental abundances are relatively accessible in these objects. In this talk I will review the major studies that, through the analysis of PN abundances, have offered constraints to the chemical evolution of the Galaxy. I will also present the most recent results of PN abundance analysis relative to Galactic and Magellanic Cloud PNe, and discuss the chemical impact of AGB stars in different metallicity environments.

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Post-AGB phase of stellar evolution Szczerba, Ryszard Post-AGB phase of stellar evolution is still not well understood. To make a progress in this field, we searched for various informations about proto-planetary nebulae and built a catalogue of post-AGB objects. Based on collected data for more than 300 objects we were able to trace the evolution of stars in their late stages with the distinction between carbon and oxygen-rich objects. Our special attension focused on spectral features seen in ISO data and clues for AGB nucleosynthesis. To improve our understanding of stellar evolution (and especially mass loss at the end of AGB/begining of post-AGB) we compare the collected data with results of our 1D hydrodynamical models.

The singular contribution of AGB stars to our understanding of galactic dynamics Demers, Serge, Battinelli, P. Bright intermediate-age stars seem to be naturally suited probes to investigate the structure and the kinematics of outer fringes of galaxies, regions where no young luminous stars are seen. The fact that it is difficult to pinpoint their intrinsic luminosity has, however, hindered somewhat their used to study the Milky Way. This drawback is of no importance for carbon stars in nearby galaxies because their membership is guaranteed by their apparent magnitude and the lack of foreground Galactic contamination. We shall show that the spatial distribution of C stars in nearby dwarf galaxies suggests a dichotomy of their outer structure. Radial velocities of C stars have so far been obtained in a few dwarf irregulars. The interpretation of their kinematics has revealed some unique and interesting properties. For most Local Group galaxies, 8 or 10 m class telescopes are needed to achieve the required velocity accuracy. Therefore, progress is slow.

C- and O-Miras and Galactic Structure Feast, Michael The paper, based on recent work, will cover the following topics. 1. The kinematics, absolute magnitudes, ages and masses of galactic Miras. 2. The relation between C- and O-Miras as indicated by their galactic kinematics. 3. Miras and the thick/thin discs. 4. Differences between Miras in the Bulge and the Disc. 5. High velocity C-Miras

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The Impact of LSST on the AGB Star Research Ivezic, Zeljko The Large Synoptic Survey Telescope (LSST) is a proposed ground-based 8.4meter telescope with a 10 square degree large field of view equipped with a 3200 megapixel camera. Starting in 2012, LSST will observe 20,000 square degrees of sky every three nights in two photometric bands, with faint limits corresponding to V=24.5. This campaign, with about 1000 visits per field, will open a movie-like window on objects that change brightness, or move, on timescales ranging from 10 seconds to 10 years. The survey will have a data rate of about 30 TB/night, and will collect over 60 PB of data over its 10-year long lifetime, resulting in an incredibly rich and extensive public archive that will be a treasure trove for breakthroughs in many areas of astronomy. I will describe how this archive will impact the AGB star research.

Conference summary Habing, Harm

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Poster Presentations

P01 Rapidly evolving Mira variable LX Cygni Barzdis, Arturs The observations of the SC-spectral type Mira variable LX Cygni, obtained with the Schmidt telescope of the Baldone observatory during more than 30 years are presented. It has been found that the period of the pulsations of the LX Cygni is dramatically increasing in good agreement with the results derived by other authors. We note that the pulsation amplitude in R(0,63) band has decreased linearly over the time until the AAVSO visual observations show nearly sinusoidal amplitude variations about a constant mean value. Such a behavior was neglected in other studies. Only a few Mira variables show such a dramatic period changes and accordind to the theory of AGB evolution, these secular changes ar expected to occur during the thermal pulses.

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P02 A New Approach to Numerical Modelling of Circumstellar Dust Shells Around Pulsating AGB Stars Bolte, Jan, Patzer, A.B.C., Galuba, G., Lingnau, K., Sedlmayr, E. A time–dependent numerical description of dust forming circumstellar envelopes around pulsating AGB stars has to account for a variety of very different physical and chemical processes leading to a system of multi–scale, highly non–linear coupled partial differential equations. The standard approaches for modelling such complex systems discretise first the time, which gives in every time step a boundary value problem in space. This allows for adaptively designed meshes in space, but fixes the same time discretisation in every spatial grid point. However, aiming at a detailed modelling of processes with very different time scales as, for example, including a non–equilibrium chemistry into a dynamical model of circumstellar dust shells around cool, late–type stars on the AGB it is fundamental to permit different time discretisations in the grid points. Consequently, we present a new numerical approach, which discretises first the space with the method of lines and thus yields a system of ordinary differential equations (ODEs) in time for every spatial grid point. A highly sophisticated stand-alone time integrator can therefore be applied to the stiff ODE systems to solve such problems. The space discretisation is done with the discontinuous Galerkin method of first order, which is known to deal very well with shock-fronts. Embedded into a moving mesh method, we obtain also adaptively designed meshes in space. We give first results on this new modelling approach and discuss further extensions and perspectives.

P03 Far-infrared diagnostic features of forsterite crystal Chihara, Hiroki We will report results of laboratory spectroscopic measurements on chemical and thermal dependency of far-IR absorption features for olivine crystal, which is considered as a promising candidate of circumstellar mineral species around oxygen-rich AGB stars. The prepared samples were synthesized polycrystalline olivine of which the chemical compositions were Fo99, Fo97 and Fo95. We focused on the absorption features located at 49 and 69-micron meters, the correlation between their peak positions and peak widths were examined. In the future, we can put some constraint on the physical and chemical conditions of circumstellar dust and its formation regions by means of correlation studies among feature parameters of absorption peak such as peak position, width, intensity and so on.

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P04 The Carbon Star Dust Sequence: Evolution of the Silicon Carbide Dust Circumstellar Outflows of Carbon Stars Corman, Adrian There have been several investigations of the evolution of the mid-infrared (IR) dust features in carbon star spectra based on IRAS LRS data, but these studies are somewhat contradictory. In order to understand these differences in interpretations and to develop an understanding of the carbon star dust condensation sequence, we have re-examined 26 IRAS LRS spectra of carbon stars that have also been observed spectroscopically by ISO SWS. The higher resolution of the ISO data and their broader wavelength coverage allows a more accurate fitting of the underlying continuum, which has a huge effect on the continuum-divided and continuumsubtracted spectra used to analyze trends on the shape, strength, and position of the mid-IR features. We found that there does not appear to be any correlation between the SiC features and the continuum temperature. In addition, we performed radiative transfer modeling using DUSTY to examine whether we should expect such correlations. The effects of parameters such as the effective temperature of the star, temperature at the inner dust radius, dust composition, optical depth and dust density distribution on the strength of the ∼11 micron SiC features. We found that limiting these parameters to a reasonable range leads to degeneracies in the shape of the spectrum in the IRAS wavelength range. We discuss the implications of these findings.

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P05 Constraints on AGB models from s-process nucleosynthesis. Cristallo, Sergio, Straniero O., Gallino, R., Piersanti, L. Thermally pulsing AGB stars with mass lower than about 3 M play a fundamental role in the Galactic enrichment of heavy elements. Their s-process nucleosynthesis is responsible of the production of the so called it main component. Two neutron sources should be considered: the 22 Ne(α,n)25 Mg reaction, which is marginally activated at the base of the convective regions generated by thermal pulses (TPs), and the 13 C(α,n)16 O reaction, the major source of neutrons, operating during the interpulse phase. The amount of 13 C required by observations can be obtained if, at the epoch of the third dredge up (TDU), some protons are diffused from the H-rich envelope into the underlying radiative He-rich (and 12 C-rich) intershell zone, thus allowing the formation of the so-called 13 C pocket through proton captures on carbon nuclei. The efficiency of this diffusive process cannot be easily predicted on the base of first principles. However, spectroscopical measurements of element overabundances in AGB stars and precise determinations of isotopic compositions of meteoritic SiC grains provide strong constraints on the amount of the 13 C hold in the pocket. They generally show a good agreement with the nucleosynthesis predictions obtained by assuming M(13 C)∼3x10−6 M , corresponding to the standard -ST- case defined by Gallino et al. 1998, even if a certain spread is often required. Here, according to the results of hydro-dynamical simulation modeling turbulent convection at the inner border of a stellar envelope, we assume that the average velocity of the convective eddy smoothly drops following an exponential law. In this way, we obtain the formation of the 13 C pocket after each TDU episode; the extension in mass of the pockets decreases pulse after pulse along the AGB path. Full stellar models calculations at different metallicites, including an extended nuclear network (from H to Bi), are presented. In particular, we follow typical TP-Interpulse-TP sequences of a star with initial mass M=2 M and Z=10−4 , under different assumptions for the strength of the exponential drop of the eddy velocity at the inner border of the convective envelope. By analysing the resulting 13 C pockets, we show how to constrain the efficiency of the proton diffusion at the epoch of the third dredge up.

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P06 Observations of the AGB star IRC+10216 from milliarcsec to arcmin spatial scales de Castro Leao, Izan, de Laverny, P., Mekarnia, D., De Medeiros, J.R., Vandame, B. We present the dusty circumstellar envelope of the AGB star IRC+10216 observed with the ESO/NACO and FORS1 instruments. On milliarcseconds scales, the central regions close to the central star appear very asymmetric and their morphology strongly vary from the J to L bands. Temporal variations are also reported. On arcmin scales, the arclet structure found in the very extended envelope are resolved in very thin shells owing to the good spatial resolution of our image. A global view by combining both scales is also presented.

P07 Optical and Infrared Properties of a Sample of Carbon Stars De Mello, Ana Beatriz, Lorenz-Martins, S. With an observed sample of circa 40 AGB carbon stars, we developed an extended classification system for these carbon-rich objects based on the most relevant classifying indexes available (Keenan 1993 and Morgan et al. 2003). The extension incorporated, that also represented the major advantage of this system of classification, is the combination of the common optical indexes with novel infrared ones. This new system presents the common C2 -, j-, MS- (based on the strengths of the SiC2 bands) and population indicators, and the new SiC- (SiC/C.A. abundance estimation), τ- and temperature indexes. The values for the infrared indexes were obtained trough a Monte Carlo simulation of the radiative transfer in the circumstellar envelopes of the stars. The full set of indexes, when applied to our sample, resulted in a more efficient system of classification, since an examination in a wide spectral range allows us to obtain a more complete scenario for the carbon stars. By analysis of the values of the classifying indexes acquired, we sought to establish a relationship between the SiC-index in the envelope and the ages of the carbon-rich AGB stars. The study of this relationship can contribute significantly to the establishment of the role of AGB stars, specially the carbon-rich ones, as tracers of the age of the galaxies.

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P08 Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles Decin, Leen, Hony, S., de Koter A., Justtanont, K., Tielens, A.G.G.M., Waters, L.B.F.M. Mass loss plays a dominant role in the evolution of low mass stars while they are on the Asymptotic Giant Branch (AGB). The gas and dust ejected during this phase form a major contribution to the interstellar medium. Recent studies have hinted towards the importance of time variability of the mass-loss rates of such objects. By modelling the full line profiles of low excitation CO transitions emitted in the circumstellar envelope, we can study the mass-loss history of AGB stars. We therefore have developed a non-LTE radiative transfer code, which calculates the velocity structure and gas kinetic temperature of the envelope in a self-consistent way. The resulting structure of the envelope provides the input for the molecular line radiative calculations which are evaluated in the comoving frame. The code allows for the implementation of modulations in the mass-loss rate. This code has been benchmarked against other radiative transfer codes and is shown to perform well and efficiently. The model is applied to the well-studied case of VY CMa. We show that both the observed integrated line strengths as well as the spectral structure present in the observed line profiles, unambiguously demonstrate that this source underwent a phase of high mass loss (∼ 2.8 × 10−4 M /yr) some 1000 yr ago. This phase lasted some 100 yr, and was preceded by a low mass-loss phase (∼ 1 × 10−6 M /yr) taking some 800 yr. The current mass-loss rate is estimated to be in the order of 1 × 10−4 M /yr. We conclude that the relative strength of the CO rotational lines in combination with the (non)-occurrence of spectral structure in the profile provide strong diagnostics to pinpoint the mass-loss history of evolved stars.

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P09 SiO2 Around O-rich AGB Stars - Astromineralogy & The ”13µm” Feature DePew, Kyle Approximately half the oxygen-rich AGB stars to be investigated spectroscopically exhibit a feature at ∼13µm. It has been shown that the 13µm feature is found more often in the spectra of semi-regular variable stars than those of Miras. The presence of the feature in supergiant spectra is rare (Speck et al. 2000). Furthermore, the 13µm feature has been correlated with various other spectral features, although these correlations are not universally accepted. The carrier of this feature has not yet been unequivocally identified, but has been attributed to various dust species, including corundum (alpha-Al2 O3 ), spinel (MgAl2 O3 ) and silica (SiO2 ). Recently it has been shown that spinel is unlikely to be the carrier of the 13µm feature (DePew et al. 2006), but both corundum and silica remain contenders. In order to constrain the carrier of the 13um feature, we use the one-dimensional radiative transfer code DUSTY to model the effects of composition and optical depth on the shape and strength of the emerging 13um feature from various silica-silicate and silica-oxide mixtures, as well as explore the effects of different grain morphologies on scattering and absorption cross-sections. These spectra are then compared to the observed spectra which exhibit the 13um feature. We show that silica is a good candidate for the carrier of the 13um feature and discuss how it fits into the bigger picture of stardust formation, including its relation to evidence from theoretical and laboratory studies.

P10 The mineralogy of dust around evolved stars in the Magellanic Clouds Dijkstra, Catharinus We investigate the mineralogy of dust around evolved stars in the Large and Small Magellanic Clouds (LMC and SMC). Our aim is to constrain the dust formation process around these stars, the enrichment of the interstellar medium with new dust, and the nature of dust that eventually goes into new planetary systems. Using Infrared Space Observatory (ISO) and Spitzer Space Telescope (SST) spectra, we present a detailed inventory of the mineralogy of the dust. We classify the spectra according to the morphology of observed spectral features, and derive the mineralogy from these features.

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P11 High-Resolution Near-Infrared Speckle Interferometry and Radiative Transfer Modeling of the OH/IR star OH 26.5+0.6 Driebe, Thomas We present near-infrared speckle interferometry of the OH/IR star OH 26.5+0.6 in the K’ band obtained with the 6m telescope of the Special Astrophysical Observatory (SAO) in Oct. 2003. At a wavelength of lambda = 2.12 micron the diffraction-limited resolution of 74 mas was attained. The reconstructed visibility function shows that the stellar contribution to the total flux at lambda = 2.12 micron is less than ∼50 %, indicating a rather large optical depth of the circumstellar dust shell (CDS) surrounding this highly reddened object, which is in accordance with the strong silicate absorption feature seen in the spectral energy distribution (SED). With respect to the asymmetry found from the recent VLTI/MIDI observations in the mid-infrared (Chesneau et al. 2004, A&A 435, 563), and from L-band observations (Starck et al. 1994, A&A 283, 349), we carefully checked our K-band data for signs of asymmetry, but given the accuracy of our measurements, no such asymmetry could be detected. Our modeling approach follows a similar strategy as it was recently successfully applied to interpret observations of the OH/IR star OH 104.9+2.4 (Riechers et al. 2005, A&A 436, 925). For the radiative transfer modeling of the CDS of OH 26.5+0.6 with the code DUSTY, we used our K-band vibility data from 2003 as well as the ISO spectrum as observational input. Since OH 26.5+0.6 is a LPV, both observations are associated with different phases of the object’s variability cycle. While the ISO observations were carried out close to minimum phase (phi=0.5), our K-band visibility data correspond to phi=0.13. From our analysis, we derived several physical parameters of the central star and the CDS for these two phases and found a phase dependence similar to the results for OH 104.9+2.4. Since OH 26.5+0.6 was recently also observed with VLTI/MIDI, we finally discuss the implications of the MIDI results with respect to our model.

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P12 Mid-infrared long-baseline interferometry of the symbiotic Mira star RX Pup with the VLTI/MIDI instrument Driebe, Thomas, K.-H. Hofmann, K. Ohnaka, T. Preibisch, G. Weigelt and M. Wittkowski We present mid-infrared long-baseline interferometric observations of the symbiotic Mira star RX Pup obtained with the VLTI/MIDI instrument within the framework of the Science Demonstration Time program in February 2004. Four visibility measurements have been obtained using the unit telescopes UT2 and UT3, with projected baseline lengths ranging from 34.7 to 46.5 m. All visibility measurements show a distinct wavelength dependence: A rather steep decrease between 8 and 10 micron, and a shallower monotonic increase longward of 10 micron. For the corresponding uniform disk diameter, this visibility shape translates into a diameter increase by a factor of 2 from 25 to 50 mas between 8 and 10 micron and an almost wavelength independent diameter between 10 and 13 micron. As we show by means of radiative transfer modeling with the code DUSTY, this wavelength dependence detected with VLTI/MIDI can be well understood in terms of a circumstellar dust shell which is dominated by silicate dust.

P13 Statistical properties of galactic carbon star based on 2MASS Eglitis, Ilgmars In the 2MASS catalogue 6620 carbon stars have been identified. Distribution of their color indices was investigated and compared with M-type stars. It is concluded that in the interval (J-K)o¡1.7 mag color indices of carbon stars overlap with G-, K-, and M-type stars but stars with (J-K)o¿2.2 mag practically all are carbon stars. Taking a fixed brightness M(K)=-8.1 mag for N-type stars and M(K)=-2 mag. for early carbon stars interstellar redening and distances have been determined. Distribution of carbon stars in the Galactic plane shows some resemblance of the spiral pattern drawn from young stars and Galactic clusters but in a global scale is highly asymmetric due to great influence of local dust clouds on survey limits. The vertical scale height zo was found for N-type stars and for early carbon stars 0.39 and 1.2 kpc corespondingly. Periods of carbon variables with P¡400 days show approximately linear increase with the color index (J-K)o. This publication makes use of data products from the Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, California Institute of Technology, funded by the NASA and the National Science Foundation.

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P14 Properties of the circumstellar envelope of the dual chemistry postAGB Roberts 22 ´ Epitacio Pereira, Daniel N., de Araujo, F.X., Lorenz-Martins, S., Ercolano, B., Barlow, M.J., Bowey, J.E. A major discovery by the ISO satellite was the presence, in the spectra of many evolved stars, of an array of narrow emission features longwards 17µm that could be attributed to crystalline silicate grain species, both enstatites and olivines. The occurrence and mineralogy of these features has been investigated in a series of papers by Molster et al. (2002), where it was concluded that for many of the sharpest featured sources the crystalline silicates are located in cool circumstellar envelope, rather than in outflows. As the envelope is formed from the continuous mass loss of the object during its AGB stage, it is natural to suppose that the central star would share its chemical properties. Thus, one would expect the star surrounded by such silicate-rich material to be oxygen-rich. However, crystalline silicates are frequently associated with carbon-rich central objects. These dual chemistry objects present an opportunity to investigate the mechanisms of mass ejection that forms the circumstellar envelope during and after AGB stage, and contribute to the enrichment of the interstellar medium. In this work we present Gemini TReCS long-slit 17-25µm spectra of Roberts 22, a post-AGB with dual chemistry. We have modeled this star using a Monte Carlo simulation method to describe the radiative transfer in its circumstellar dust envelope. We have considered three different species of grains: amorphous carbon, crystalline and amorphous silicate to describe the circumstellar matter.

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P15 OH26.5+0.6: insight in an extreme OH/IR star Etoka, Sandra, Diamond, P. OH/IR stars are an important stage in the life of an AGB star. This short transitional phase towards the proto-planetary stage is a crucial point in the life of an intermediate- or high-mass star. Indeed, the mass-loss rate when a star reaches this stage is at its highest. The resulting circumstellar shell - interface between the central object and the interstellar medium - is a rich environment of dust and molecules. It is at this stage that asymmetries are detected, even in the outermost part of the circumstellar shell where OH radicals are formed. OH26.5+0.6 is an extreme OH/IR star: one of the brightest OH maser emitters in our Galaxy. Its current mass-loss rate is estimated to be in the order of 5 x 10−4 solar mass per year corresponding to a superwind phase started hardly 150 years ago. MERLIN OH observations at 18 cm in the 1667, 1665 and 1612 MHz maser line allowed the first combined insight in the geometric and polarimetric structure of this object. The maser spots show a spheroidal distribution both at 1612 and 1667 MHz while at 1665 MHz a filamentary structure oriented on an NW-SE axis is observed. The velocity distribution of the maser spots according to the radial distance is well explained by an isotropic outflow at constant velocity in the prolate case. And, the polarization vectors show a highly structured distribution. This work intends to bring a new insight in the change of structure undergone by an evolved star when it enters the OH/IR stage.

` wave driven winds in AGB stars P16 Afven Falceta-Goncalves, Diego ` waves are supposed to play an important role on the wind acceleration of Alfven luminous late-type stars. In these models, an outward directed wave flux, guided by the flux tube field lines, is damped transferring momentum and energy to the gas. The flux tube geometry is important for the terminal velocity of the wind and typical super radial divergences (e.g. solar coronal holes) imply in lower wind velocities. The super radial factor is, in general, introduced in the models as an ad hoc parameter, based on empirical results of the solar coronae. In this work we performed a self-consistent determination of the magnetic field geometry based on the tension generated by the gas pressure gradient inside the flux tube as it is heated by the wave damping. We also compare the wind temperature and velocity profiles of this model with the results obtained for a non self-consistent field geometry.

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P17 The Problem of Masses for Single Field Red Giants Garrison, Robert This is a reminder that the Red Giant clump contains a large range of masses, so without a cluster or double star it is not easy to determine the masses. Examples will be given.

P18 AGB circumstellar environments probed through the 21 cm atomic hydrogen emission. Gerard, Eric & Le Bertre, Th. Red giants play an important role in the recycling of matter in interstellar space. Most of the material in circumstellar shells around red giants is hydrogen (∼ 70% in mass), in atomic (or molecular) form. However, up to now, atomic hydrogen has remained largely undetected due to the weakness of its emission and to the competing emission from interstellar hydrogen on the same line of sight. With the upgraded Nancay Radiotelescope (NRT), we have undertaken a new high sensitivity search for the atomic hydrogen emission line at 21 cm in the direction of red giants, AGB stars and post-AGBs including PNs. The fan beam shape (4’ x 22’) of the NRT allows a good East- West discrimination of circumstellar envelopes against the galactic HI background. We present our results on a few closeby sources which reveal circumstellar HI emission that may extend out to ∼ 1 pc. These observations are complementary to the CO data which probe the inner parts of the envelopes. They can be used to study the mass loss history of red giants over long time scales (∼ 100,000 years) but also to investigate the interaction between stellar outflows and the ambient ISM.

P19 Contribution of Stellar Mass-Loss to the Interstellar Medium (tentative) Glass, Ian It is intended to make an audit of the contributions of various types of mass-losing stars to the interstellar medium.

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P20 New observations of the VLTP objects Hajduk, Marcin, Zijlstra, Evans, Kerber, van Hoof, Pollacco, Eyres, Kimeswenger, Gesicki V4334 Sgr and V605 Aql, which are believed to represent objects during the Very Late Thermal Pulse (VLTP), have been re-observed at radio continuum. The observations are consistent with theoretical post-AGB evolution models. The radio detection of V4334 Sgr is confirmed. We find an increasing radio flux consistent with an increase of the central star temperature for V605 Aql. We also describe two more unique objects, which may be related to VLTP events: the old nova CK Vul, and the central star of the planetary nebula M2-29. For CK Vul we found an unresolved radio emission source which probably reveals the position of the central star candidate. Optical images reveal a large bipolar nebula. An long lasting extinction event is detected in the central star of M2-29, similar to R CrB events but on a much longer time scale. HST images reveal a peculiar but unexplained morphology of the planetary nebula.

P21 AGB Common Envelope Evolution as Observed in the HR4049 PostAGB Stars Hinkle, Kenneth High-resolution infrared spectroscopy in the 2.3-4.6 micron region is reported for the peculiar binary star HR 4049. HR 4049 has severe depletion of refractory elements but near solar abundances of volatile elements. The infrared spectrum of CO, OH, and H2O lines are shown to originate in a circumstellar disk. The disk is rotating and is the site for separating the refractory and volatile elements. The rotation velocity of the disk combined with the single lined spectroscopic binary orbit allows the masses of the individual stars to be computed. The system has previously undergone common envelope evolution. Mass transfer from the M dwarf secondary to the AGB primary changed the circumstellar remnant from carbon-rich to oxygenrich.

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P22 A Long-Term Study of Pulsaational Light Variability in Post-AGB Stars Hrivnak, Bruce, Wenxian Lu We are carrying out a long-term study of light variability in proto-planetary nebulae (PPNe), objects in transition between the AGB and PN phases of stellar evolution. These consist of central stars with spectra of B-G supergiants surrounded by expanding, detached envelopes of molecular gas and dust. This observing program has been carried out since 1994 at the Valparaiso University Observatory using the 0.4-m telescope and CCD camera. Approximately 20 PPNe and an additional 15 PPN candidates are being observed. All of the PPNe and most of the PPN candidates show light variability. Focusing on the PPN sample, light variations range from 0.1 to 0.5 mag. Periods are found for a third of the sample, all of which have F and G spectral types. None of those with B-A spectral types show a dominant period but vary on a timescale of 1 week or less. For those with F-G spectral types, half show a dominant period of 45-135 d; those without a dominant period show variations on a time scale of several months. Even those with a dominant period do not have a simple periodic light curve; either they vary in amplitude or have multiple periods or both. This has necessitated a long-term study. The observed trend of shorter time scale variations with higher temperatures fits the general expectations of a smaller atmosphere as these stars evolve toward higher temperatures at constant luminosities. These results will be used to constrain models of the post-AGB, PPN nature of these stars.

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P23 The ASTRO-F Survey of the Large Magellanic Cloud Ita, Yoshifusa The Japanese infrared space telescope ”ASTRO-F” was successfully launched on February 22 2006. ASTRO-F is equipped with a diameter of 68.5cm cooled telescope and two scientific instruments, namely the Infrared Camera (IRC) and the FarInfrared Surveyor (FIS). The IRC has nine imaging filters covering the wavelength range from 2 to 26 microns and F.O.V.s of about 10’x10’. The FIS will observe in four far-infrared bands between 50 and 180 microns. In addition, both instruments have low- to moderate-resolution spectroscopic capability. A major goal of the ASTROF mission is to carry out an All-Sky Survey with the FIS, and additionally with the IRC at 9 and 18 microns. In addition to the All-Sky Survey, ASTRO-F will carry out thousands of dedicated pointed observations with both the IRC and FIS. With this opportunity, we will carry out an imaging/slit-less spectral mapping observation covering about 15deg2 of the Large Magellanic Cloud. We will use 5 imaging filters centered roughly on 4,7,11,12, and 24 microns, and also 1 slit-less prism with a central wavelength of about 3.5 micron. Together with the FIS/IRC All-Sky Survey products, these data should play a complementary role to the results from the Spitzer SAGE project. In the poster, we will introduce this ASTRO-F LMC large area survey project with an emphasis on the AGB study. The data produced by our survey are ideal to detect dust mass loss from AGB stars, as well as to see luminosity function of these stars.

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P24 Detection of an 0.1 pc dust shell of the carbon star U Hydrae through optical light Izumiura, Hideyuki, Nakada, Y., Hashimoto, O., Mito, H., Hayashi, T. We report the detection of a detached, very extended optical shell around a carbon star U Hya in V-band. The shell looks circular and has a radius of about 120” (0.1 pc), which is fully consistent with the dust shell resolved in the high resolution IRAS image at 60um (Waters et al. 1994, AA, 281, L1). The shell reflects in total about 1/6000 of the star light in V-band. Radial profile of the shell brightness shows a clear maximum at 115” and a rapid decline to the rim at 130”. The radial profile indicates the shell is probably geometrically thin, while spherical symmetry is assumed for the shell. The peak brightness of the shell at V-band is roughly 25th magnitude per square arcsecond. The optical shell is probably seen through the scattered light of the central star by dust grains. Dust mass in the shell is estimated to be 10−5 Solar Mass with some simple assumptions on the dust grain properties. Because no such extended CO gas shell is known for U Hya, this becomes the first instance of an opitical dust shell detected far beyond the CO photodissociation radius. Variation of the shell brightness due to the light variation of the central star is under investigation. The origin of the thin detached dust shell is also discussed.

P25 The AGB contribution to Galactic chemistry Izzard, Robert, Gibson, B. I shall present a poster describing the first application of new results based on work I have done in Utrecht (with Maria Lugaro, Amanda Karakas of McMaster University and Christian Iliadis of the University of North Carolina) regarding the chemical yields of neon and sodium from hot-bottom burning AGB stars. We have adapted my rapid single/binary stellar evolution/population nucleosynthesis code to allow variation of NeNa and MgAl cycle reaction rates during hot bottom burning. I have tied my stellar evolution code directly into a dual-infall chemical evolution model of the solar neighbourhood in order to determine the effect of varying the yields of neon and sodium on local stellar abundances. With the help of GCE expert Brad Gibson (University of Central Lancashire) I will compare the simulation results to observed neon and sodium abundances in nearby stars and planetary nebulae.

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P26 NIR monitoring of the Arecibo sample of OH/IR stars Jimenez-Esteban, Francisco In order to study the variability properties of the ‘Arecibo sample’ (periods, amplitudes, and colour variations) we performed a near-infrared monitoring program from 1999 to 2005. A subsample was also monitored optically. Althoght the data are already under analysis we present in this poster the first preliminary results of this multi-wavelength long-term monitoring program. Our ultimate goal is to study in particular the oxygen-rich AGB stars with masses larger than 2 solar mass which are probably rare among AGB stars discovered optically and in the near-infrared, but are common in samples discovered by blind OH maser surveys.

P27 The anomal chemical composition of Cyg X-1 optical component Karitskaya, Eugenia We report the results of Cyg X-1 spectral observaitions over 2002-2004. The comparison of observed and non-LTE model profiles for HI, HeI and MgII is given taking into account tidal distortion of Cyg X-1 optical component and its illumination by Xray emission of secondary one. We set restrictions on the optical component main characteristics T e f f = 30400 ± 500K, log g = 3.31 ± 0.07 and overabundance of He and Mg: [He/H] = 0.43dex, [Mg/H] = 0.59dex. Also we found overabundances of Si, N, C and O with Al solar abundance.

P28 Shape effects and temperature effects on infared spectra Koike, Chiyoe We present about shape effects and temperature effects on infrared spectra of forsterite partiles.

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P29 19 F production in AGB: indirect measurements of the 15 N(p,a)12 C astrophysical S(E) factor La Cognata, Marco Large uncertainties can be introduced by direct measurement of nuclear reaction cross sections inside the Gamow peak because of extrapolations from higher energies. In fact cross sections are very low because of the Coulomb suppression, thus even small backgrounds make them inaccessible in the relevant energy window. In addition the electron screening effect is responsible of the enhancement of cross sections at ultra-low energies so extrapolation is again required to extract the nuclear cross section that is the relevant input for astrophysics. In this work we report on the indirect technique named ‘Trojan Horse Method’, allowing to extract nuclear cross sections with no need of extrapolation. In particular the improved measurement of 15N(p,a)12C cross section down to 5 keV is discussed. The 15N(p,a)12C cross section is an important input for astrophysics since it is involved in AGB 19F nucleosynthesis. In fact the 15N(p,a)12C reaction removes both protons and 15N nuclei from 19F production chain. The astrophysical S-factor is extracted and compared with previous measurements, showing a lower S(0) in disagreement with the value suggested by the NACRE compilation.

P30 Water Opacity in M Stars Lederer, Michael, Aringer, B., Kerschbaum, F. The atmospheric structure as well as the infrared spectral appearance of cool Mtype stars are dominated by the opacity of water. We compare the different available line lists for water (Partridge & Schwenke 1997, Jørgensen et al. 2001, Barber et al. 2006) concerning their impact on hydrostatic/dynamic models for cool giants and the emerging synthetic spectra. Special emphasis will be put on the 2.5-10 µm interval which is of particular importance for the low temperature layers where stellar winds are accelerated. The synthetic spectra for this range are compared to ISO-SWS observations.

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P31 What 1612 MHz masers tell us about the dM/dt of OH/IR Stars Lewis, (Brian) Murray The pump for 1612 MHz masers depends on the reprocessing of stellar radiation by dust in the near environs of the star. Hence the NIR colors of OH/IR stars, in combination with their MIR colors, provide a diagnostic for the current dM/dt of a star, whether it is basically switched ON or OFF. There are several situations in practise. Many OH/IR stars show evidence for detached shells that result from a deep modulation in their rates of dM/dt. When the peak dM/dt is modest, this can lead to a cyclical switching ON/OFF of the 1612 MHz masers in phase with the modulation in dM/dt: we now have 5 instances of 1612 MHz masers switching OFF, and one that has subsequently switched ON again. On the other hand when a star progresses to the PPN phase, its masers switch OFF permanently, though they appear to take far longer to do so. This is evidence for the final rate of dM/dt being an order of magnitude larger than the time averaged value.

P32 Spectral variations in fading episodes of carbon stars. Lloyd Evans, Tom Spectroscopic monitoring of six carbon stars for fifteen years has shown spectacularly unusual features during faint episodes which were observed to occur in three of them. These took the form of emission in C2 bands and resonance lines of NaI, KI and RbI, according to two different patterns: peculiarities appearing relatively independent of wavelength (R Lep, V Hya) and confined to short wavelengths only (T Mus). This second phenomenon has been observed, more weakly, in carbon Miras at certain phases and may result from atmospheric stratification. The wavelengthindependent emissions in R Lep and V Hya may indicate mass loss.

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P33 Modelling dead OH/IR stars Lorenz-Martins, Silvia OH/IR present several OH maser emission lines which are located in the outer regions of their circumstellar dust evelopes. These stars can be recognized at large distances, based only on radio and infrared observations. Then they can be used as kinematic tracers in galaxies. The emission at 1612 MHz is the strongest line and present a double profile (Dv=20-50 Km/s). Only in the planetary nebulae phase this line is sometimes no longer detected. In this work we calculated radiative transfer models to describe dust envelopes of an OH/IR sample. For the sample, the maser emission at 1612 MHz has disappeared. We also included some OH/IR in which this maser emission was recently detected. The results show that the physical parameters for the dust envelopes of almost all sample are the same that those expected for normal oxygen-rich AGB stars. However 3 sources have different pattern: they present a double peak SED which can be due to an evolved dust envelope.

P34 Modeling of circumstellar H2 O line emission from M-type AGB stars ¨ Maercker, Matthias, Olofsson, H., Schoier, F.L. We present initial results of a modeling of circumstellar H2 O line emission towards four M-type AGB stars: W Hya, R Dor, R Cas, and TX Cam. The mass loss rates are determined from CO radio line modeling and range from about 2x10−7 M yr−1 to 7x10−6 M yr−1 . Also the kinetic temperature distribution is determined from the CO modelling. An accelerated lambda iteration code is used to handle the high optical depths of water vapour. Energy levels in the ground and first excited rovibrational state of ortho-H2 O are included. The dust temperature and optical depth are determined by fitting the spectral energy distribution (SED) using DUSTY, and the resulting dust radiation field is also included in the excitation calculation. The resulting H2O model line intensities are fit to ISO LWS data between 45 and 180 µm. Our results confirm the high abundance of ortho-H2 O previously detected in W Hya (1x10−3 relative to H2 ), with ortho-H2 O abundances for the other objects somewhat lower but of the same order of magnitude.

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P35 CS 30322-023: an ultra metal-poor TP-AGB star? Masseron, Thomas, Van Eck, S., Famaey, B., Goriely, S., Plez, B., Siess, L., Primas, F., Jorissen, A. With [Fe/H] = -3.5, CS 30322-023 is the most metal-poor star to exhibit a clear s-process signature and the most metal-poor “lead star” known. CS 30322-023 is also remarkable in having the lowest surface gravity (log g 1 in the photosphere), respectively. Average SiO fractional abundances were obtained from a detailed (NLTE) radiative transfer analysis of multi-transition single-dish observations. Interestingly, for the M-type AGB stars the derived abundances are generally much lower than expected from photospheric equilibrium chemistry. For the carbon stars, on the other hand, the derived abundances are on the average two orders of magnitude higher than predicted by photospheric equilibrium chemistry. In fact, when comparing the two distributions of SiO fractional abundances there appears to be no way of distinguishing a C-rich chemistry from that of an O-rich based on an estimate of the circumstellar SiO abundance alone. Moreover, there is a clear trend that the SiO fractional abundance decreases as the mass-loss rate of the star increases, as would be the case if SiO is accreted onto dust grains Further support for such a scenario comes from interferometric observations of the ¨ two M-type AGB stars R Dor and L2 Pup performed by Schoier et al. (2004, A&A ¨ et al. (2006, ApJ accepted). In 422, 651) and the carbon star IRC +10216 by Schoier their analysis they found evidence in all three cases of an inner compact component of high fractional abundance, consistent with predictions from stellar atmosphere chemistry in the case of the M-type objects but several orders of magnitude larger than expected for the carbon star IRC +10216, indicating the importance on nonLTE chemical processes. In addition, an extended low-abundance component, as expected if SiO is effectively depleted onto grains in the inner wind, was required in order to fit the observations in all cases. Consequently, there are strong indications that circumstellar SiO line emission carries information on the properties of the chemically and dynamically region where the mass loss of AGB stars is initiated. However, the conclusions still rest on rather loose ground, e.g., the constraints on the detailed SiO abundance distribution are poor (especially as a function of mass loss rate). Therefore, our knowledge of the relative importance of freeze-out onto dust grains, photodissociation, and circumstellar chemistry is still rudimentary. In a way to remedy this we have initiated a project aimed at obtaining high spatial resolution interferometric observations for a representative sample. Presented here is a first analysis of 9 AGB- stars with varying photospheric C/O-ratios and mass-loss rates that has been imaged in SiO line emission using the ATCA, SMA, and VLA.

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P54 Using LPVs as tracers of stellar populations applying the Fuel Consumption Theorem ¨ Snigula, Jan, Gossl, C., Hopp, U. Based on our multi-year observing campaign of a sample of six Northern Dwarf Irregular Galaxies of the Local Group we assembled a sample of long period pulsating variable stars (LPV) in these galaxies. Due to the long baseline of continuous observations in the R-Band and thorough completeness simulations this sample can be considered to be complete. To draw preliminary conclusions on the galaxies star formation history with special emphasis on the intermediate ages, two approaches were combined: a rough comparison of the observed dwarf galaxy color-magnitude diagrams with the location of different isochrones, and a prediction of the number of AGB stars based on the Fuel Consumption Theorem.

P55 Simultaneous verus non-simultaneous stellar evolution calculations of the TP-AGB Stancliffe, Richard The stellar evolution code STARS, originally developed by Eggleton (1971), solves the equations of stellar structure and chemical evolution in a fully simultaneous manner (i.e. iterating on all variables at the same time to converge a new model) unlike most codes which solve for the structure and then deal with the chemistry separately. Does this approach account for some of the differences in behaviour on the TP-AGB predicted by different codes? While it is assumed that the nonsimultaneous approach should not affect the solution (Herwig 2005), the assumption has not been tested until now. To investigate whether the use of a simultaneous approach over a non-simultaneous one affects the solution obtained, I have developed a non-simultaneous version of the STARS code. Models of 3 and 5 solar masses and a metallicity of Z=0.02 are evolved from the pre-main sequence using both the simultaneous and non-simultaneous versions of the code. While pre-AGB evolution seems to be identical in the two cases, on the TP-AGB the two methods give diverging results. The non-simultaneous case is seen to give longer interpulse periods. I discuss the importance and implications of this divergence in behaviour.

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P56 Relics of primordial AGB supernovae in Galactic metal-poor stars Tsujimoto, Takuji Renewed interest in the first stars that were formed in the universe has led to the discovery of extremely iron-poor stars. Since several competing scenarios exist, our understanding of the mass range that determines the observed elemental abundances remains unclear. In this study, we consider three well-studied metal-poor stars in terms of the theoretical supernovae (SNe) model. Our results suggest that the observed abundance patterns in the metal-poor star BD +80 245 and the pair of stars HD 134439/40 agree strongly with the theoretical possibility that these stars inherited their heavy element abundance patterns from SNe initiated by thermonuclear runaways in the degenerate carbon-oxygen cores of primordial asymptotic giant branch stars with ∼3.5-5 solar masses. Recent theoretical calculations have predicted that such SNe could be originated from metal-free stars in the intermediate mass range. On the other hand, intermediate mass stars containing some metals would end their lives as white dwarfs after expelling their envelopes in the wind due to intense momentum transport from outgoing photons to heavy elements. This new pathway for the formation of SNe requires that stars are formed from the primordial gas. Thus, we suggest that stars of a few solar masses were formed from the primordial gas and that some of them caused thermonuclear explosions when the mass of their degenerate carbon-oxygen cores increased to the Chandrasekhar limit without experiencing efficient mass loss.

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P57 UVES spectroscopy of galactic bulge AGB stars: A search for Technetium and implications for dredge-up ¨ Uttenthaler, Stefan, Hron, J., Lebzelter, T., Busso, M., Schultheis, M., Kaufl, H.-U. Using high resolution optical spectra obtained with the UVES spectrograph at ESO’s VLT we search for resonance lines of neutral Technetium in the blue spectral region of asymptotic giant branch (AGB) stars. The sample stars are bona-fide, long-period pulsating, oxygen-rich AGB stars located in the outer galactic bulge. Tc is an unstable element synthesised via the s-process in deep layers of AGB stars, thus it is a reliable indicator of both recent s-process activity and third dredge-up. We aim to test theoretical predictions on the luminosity limit for the onset of third dredge-up in AGB stars. These measurements allow us to improve the procedure of cassification of stars with respect to their Tc content by using flux ratios. Synthetic spectra based on MARCS atmospheric models are presented and compared to the observed spectra around three lines of Tc. Bolometric magnitudes are calculated based on near infrared photometry of the objects. Among the sample of 27 long period bulge variables four were found to definitely contain Tc in their atmospheres. The luminosity of the Tc rich stars is in agreement with predictions from AGB evolutionary models on the minimum luminosity at the time when third dredge-up sets in. However, AGB evolutionary models and current age estimates of the bulge can not be brought into complete agreement. This probably means that a population younger and slightly more massive than expected is present in the bulge and contains the Tc-rich stars here identified.

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P58 Circumstellar envelopes as AGB mass-loss signatures Villaver, Eva As stars die they inject momentum and energy into the interstellar medium (ISM) in the form of chemically enriched winds. Low-and intermediate-mass stars (1–8 M· ) lose up to 80 % of their initial mass during the Asymptotic Giant Branch (AGB), before ending as white dwarfs. Heavy mass-loss is the signature of the late AGB phase: at uncertain rates of 10−6 to 10−3 M· /yr, on timescales of 105 –106 yr, it removes up to 7 M· of stellar material. We have investigated the dynamical interaction of these winds with their local ISM by using a numerical code and the wind history predicted by stellar evolution. We find that the wind variations associated with the thermal pulses lead to the formation of transient shells with an average lifetime of ∼20,000 yr and, consequently, do not remain recorded in the density or velocity structure of the gas. According to our simulations, large regions (up to 2.5 pc) of neutral gas surrounding the molecular envelopes of AGB stars are expected. These large regions of gas are formed from the mass loss experienced by the star during the AGB evolution and are strongly linked to the assumed timescales of heavy mass-loss rates.

P59 Mass loss of AGB stars: Low Metallicity Models Wachter, Astrid Dust grains which form under favourable conditions in the cool, extended atmospheres of Asymptotic Giant Branch stars play an important role in the driving mechanism of the strong winds observed in this kind of stars at various metallicities. Due to their large absorption cross-sections these newly formed dust particles and the surrounding gas, which are frictionally coupled, are accelerated by the radiation pressure leading to a massive circumstellar outflow. In this contribution, we present hydrodynamical wind models for long-period variables which have been adapted to lower opacities resulting from lower metallicities. Furthermore, we discuss the derivation of mass-loss formulae based on extended samples of these models for different metallicities, and the mass-loss histories of single stars which result from their application to stellar evolution. Thereby, we focus on a comparison of the mass-loss of solar models and models with abundances as found in the Small and Large Magellanic Cloud (i.e. subsolar metallicity).

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P60 Diffraction-limited bispectrum speckle interferometry of the carbon star IRC +10 216 with 73 mas resolution: The dynamic evolution of the innermost circumstellar environment from 1995 to 2005 Weigelt, Gerd, Balega, Y., Hofmann, K.-H., Menshchikov, A., Schertl, D. We present a unique bispectrum speckle interferometry monitoring of the carbon star IRC +10 216 obtained between 1995 and 2005 with the BTA 6 m and the MMT 6.5 m telescope (e.g., Weigelt et al. 2002, Astron. Astrophys. 392, 131). The attained J-, H-, and K-band resolutions are 50 mas, 56 mas, and 73 mas, respectively. The total sequence of observations now covers 11 epochs (one diffraction-limited image per year) and shows the dynamic evolution of the inner dust shell in unprecedented detail. The appearance of the 4 main dust components within a 0.2 arcsec radius has changed considerably during the last few years. Our 2-D radiative transfer model suggests that the observed relative motion of the components is not consistent with the outflow of gas and dust at the terminal wind velocity of 15 km/s. The apparent motion appears to be caused by a displacement of the dust density peak due to dust evaporation in the optically thicker and hotter environment. Present monitoring shows that the structural variations are not related to the stellar pulsation cycle in a simple way.

P61 The chemical composition and evolutionary status of R stars Zamora, Olga, Abia, C., Plez, B., Dominguez, I. A full chemical analysis of 23 galactic R-stars (of both types, hot and cool) with measured Hipparcos parallaxes is presented. We have derived the C/O and 12 C/13 C ratios, the average metallicity ([M/H]), Li and s-elements abundances. We find that most of the stars have 12 C/13 C below ∼ 20 and C/O ratios in the range ∼ 1 to 2, with no significant difference between cool and hot stars. The metallicities are close to solar except for a few stars in the sample, which are suspected to be CHstars. However, a clear separation in the average Li abundance is found between the R-hot (log  (Li)= 0.9) and R-cool (log  (Li)= −0.5). Only four stars within the sample show significant s-element enhancements. Significantly, for these four stars there is evidence of binarity from previous studies in the literature. We discuss the abundance results together with the kinematic properties, location in the Galaxy and comparative HR diagram, which lead us to conclude that the R-cool stars might be identical to the normal (spectral type N) AGB carbon stars, perhaps being in a previous evolutionary stage (early AGB phase). On the other hand, the R-hot stars seem to belong to a different stellar population (lower masses), although many of them are probably misclassified CH or Ba stars.

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P62 Dust ejection by AGB stars during Galactic evolution Zhukovska, Svilana & Hans Peter Gail We study the contribution of AGB stars to the dust content of the Milky Way using chemical evolution modeling. Our model combines gas infall model of the Galaxy and multiphase model of the ISM. Evolution of gas element abundances and dust is defined by gas infall rate, feedback from evolved stars and mass transfer between components of MPISM. We consider metalicity dependant injection of carbon, iron, silicate and SiC dust species to the ISM by asymptotic giant branch stars and supernovae. Further processing of dust in the ISM, grain growth through accretion in cold molecular clouds and destruction by SN shocks is modelled. We predict the amount and composition of dust in each phase of the ISM as a function of galactocentric radius and time. Fraction of unprocessed grains from outflows of AGB stars that survived in the ISM till moment of Solar System formation is studied.

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Participants Andersen, Anja C. Dark Cosmology Centre [email protected]

Corman, Adrian University of Missouri-Columbia [email protected]

Aringer, Bernhard University of Vienna [email protected]

Cristallo, Sergio Osservatorio Astronomico di Teramo (INAF) [email protected]

Baier, Angela University of Vienna [email protected]

de Castro Leao, Izan Universidade Federal do Rio Grande do Norte [email protected]

Barzdis, Arturs University of Latvia arturs [email protected]

Decressin, Thibaut Geneva Observatory [email protected]

Battinelli, Paolo INAF-OAR [email protected]

De Mello, Ana Beatriz Observatorio Nacional - MCT [email protected]

Bernath, Peter University of Waterloo [email protected]

Demers, Serge Universite de Montreal [email protected]

Blommaert, Joris K.U.Leuven [email protected]

DePew, Kyle University of Missouri - Columbia [email protected]

Bolte, Jan ¨ Berlin Technische Universitat [email protected]

Dijkstra, Catharinus University of Missouri-Columbia [email protected]

Busso, Maurizio University of Perugia [email protected]

Dreyer, Claudia Technische Universitaet Berlin [email protected]

Castro-Carrizo, Arancha Institut de Radioastronomie Millimetrique [email protected]

Driebe, Thomas Max-Planck Institut fuer Radioastronomie [email protected]

Charbonnel, Corinne Geneva Observatory & CNRS [email protected]

Eglitis, Ilgmars University of Latvia [email protected]

Chihara, Hiroki Osaka University [email protected]

Epitacio Pereira, Daniel N. Observatorio Nacional - MCT [email protected]

Cioni, Maria-Rosa University of Edinburgh [email protected]

Eriksson, Kjell Uppsala University [email protected]

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Etoka, Sandra University of Manchester [email protected]

Habing, Harm Leiden University [email protected]

Falceta-Goncalves, Diego IAG-USP [email protected]

Haika, Anneliese ¨ Astronomie Wiener Arbeitsgemeinschaft fur [email protected]

Feast, Michael University of Cape Town [email protected]

Hajduk, Marcin Centrum Astronomii UMK [email protected]

Gallagher III, John S. University of Wisconsin-Madison [email protected]

Handler, Gerald University of Vienna [email protected]

Gallino, Roberto Dipartimento di Fisica Generale [email protected]

Hauschildt, Peter Hamburger Sternwarte [email protected]

Galuba, Goetz Technische Universitaet Berlin [email protected]

Hensler, Gerhard University of Vienna [email protected]

Garrison, Robert University of Toronto [email protected]

Herwig, Falk Los Alamos National Laboratory [email protected]

Gerard, Eric Observatoire de Paris [email protected]

Hinkle, Kenneth NOAO [email protected]

Girardi, Leo Osservatorio Astronomico di Padova [email protected]

¨ Hofner, Susanne Uppsala University [email protected]

Glasner, Ami The Hebrew University, Jerusalem [email protected]

Hrivnak, Bruce Valparaiso University [email protected]

Glass, Ian South African Astronomical Observatory [email protected]

Hron, Josef ¨ Wien Universitat [email protected]

Glassner, Eveline ¨ Wien Universitat [email protected]

Ireland, Michael California Institute of Technology [email protected]

Grebel, Eva University of Basel [email protected]

Ita, Yoshifusa Japan Aerospace Exploration Agency [email protected]

Gregg, Michael University of California, Davis [email protected]

Ivezic, Zeljko University of Washington [email protected]

Groenewegen, Martin Instituut voor Sterrenkunde, Leuven [email protected]

Izumiura, Hideyuki Okayama Astrophysical Observatory, NAOJ, NINS [email protected]

Guandalini, Roald University of Perugia [email protected]

Izzard, Robert University of Utrecht [email protected]

Gustafsson, Bengt Uppsala University [email protected]

Jackson, Dale University of Minnesota [email protected]

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Jimenez-Esteban, Francisco Observatorio Astronomico Nacional [email protected]

Lloyd Evans, Tom University of St Andrews [email protected]

Jørgensen, Uffe Graae Niels Bohr Institute [email protected]

Lorenz-Martins, Silvia Dep. de Astronomia, UFRJ [email protected]

Justtanont, Kay Stockholm Observatory [email protected]

Maercker, Matthias Stockholm Observatory [email protected]

Karakas, Amanda McMaster University [email protected]

Maitzen, Hans Michael ¨ Wien Universitat [email protected]

Karitskaya, Eugenia Astronomical Institute of RAS [email protected]

Marengo, Massimo Harvard-Smithsonian CfA [email protected]

Kerschbaum, Franz ¨ Wien Universitat [email protected]

Marigo, Paola Universita´ di Padova [email protected]

Kitsikis, Agis Max Planck Institute for Astrophysics [email protected]

Matsunaga, Noriyuki University of Tokyo [email protected]

Koike, Chiyoe Kyoto Pharmaceutical University [email protected]

Matsuura, Mikako National Astronomical Observatory of Japan [email protected]

La Cognata, Marco INFN-LNS & University of Catania [email protected]

Matthews, Lynn Harvard-Smithsonian Center for Astrophysics [email protected]

Ladjal, Djazia KU Leuven [email protected]

Mattsson, Lars Department of Astronomy and Space Physics [email protected]

Lagadec, Eric University of Manchester [email protected]

Mchunu, B. Menzi University of Missouri - Columbia [email protected]

Lamia, Livio INFN LNS and Universita´ di Catania [email protected]

Miller Bertolami, Marcelo Miguel Universidad Nacional de la Plata, Argentina - MPIA [email protected]

Lanc¸on, Ariane Observatoire de Strasbourg [email protected]

Mouhcine, Mustapha Astrophysics Research Institute, LJMU [email protected]

Lattanzio, John Monash University [email protected]

Murakawa, Koji Max-Planck-Institut fuer Radioastronomie [email protected]

Lebzelter, Thomas ¨ Wien Universitat [email protected]

Murata, Keisuke Osaka University [email protected]

Lederer, Michael ¨ Wien Universitat [email protected]

Nowotny, Walter ¨ Wien Universitat [email protected]

Lewis, (Brian) Murray Arecibo Observatory [email protected]

Ocvirk, Pierre University of Central Lancashire [email protected]

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Ohnaka, Keiichi Max-Planck-Institut fuer Radioastronomie [email protected]

Schmidt, Miroslaw Nicolaus Copernicus Astronomical Center [email protected]

Olofsson, Hans Stockholm Observatory [email protected]

¨ Schoier, Fredrik Stockholm Observatory [email protected]

Ortiz, Roberto University of Sao Paulo [email protected]

¨ Schonberner, Detlef Astrophysikalisches Institut Potsdam [email protected]

Ottensamer, Roland ¨ Wien Universitat [email protected]

Schultheis, Mathias Observatoire de Besanc¸on [email protected]

Patzer, Beate TU Berlin [email protected]

Sergi, Maria Letizia INFN-LNS & University of Catania [email protected]

Perinotto, Mario Univ. of Firenze [email protected]

Siess, Lionel IAA - Brussel [email protected]

Pitman, Karly Washington University [email protected]

Snigula, Jan Unisternwarte Muenchen [email protected]

Pizzone, Rosario INFN-LNS & University of Catania [email protected]

Smith, Verne NOAO [email protected]

Pulecka, Marta Nicolaus Copernicus Astronomical Center [email protected]

Speck, Angela University of Missouri - Columbia [email protected]

Pumo, Maria Letizia Universita´ di Catania [email protected]

Stancliffe, Richard Institute of Astronomy, Cambridge [email protected]

Raimondo, Gabriella INAF-Astronomical Observatory of Teramo [email protected]

Stanghellini, Letizia NOAO [email protected]

Ramstedt, Sofia Stockholm Observatory [email protected]

Szczerba, Ryszard N. Copernicus Astronomical Center [email protected]

Recchi, Simone Vienna University [email protected]

Teyssier, David ESAC [email protected]

Rejkuba, Marina ESO [email protected]

Theis, Christian ¨ Wien Universitat [email protected]

Richichi, Andrea European Southern Observatory [email protected]

Tosi, Monica INAF - Osservatorio Astronomico di Bologna [email protected]

Sabin, Laurence INGT/University of Manchester [email protected]

Toumi, Sihem Ferhat Abass University, Setif [email protected]

Sahin, Timur Armagh Observatory [email protected]

Tsujimoto, Takuji National Astronomical Observatory [email protected]

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Tuchman, Yitzchak Racah Inst. Hebrew University [email protected] Uttenthaler, Stefan ESO [email protected] Vanhollebeke, Evelien Instituut voor Sterrenkunde [email protected] van Loon, Jacco Keele University [email protected] Villaver, Eva Space Telescope Science Institute/ESA [email protected] Wachter, Astrid TU Berlin [email protected] Wahlin, Rurik Uppsala University [email protected] Waters, Rens University of Amsterdam [email protected] Weigelt, Gerd MPI for Radioastronomy [email protected] Weiss, Werner ¨ Wien Universitat [email protected] Willson, Lee Anne Iowa State University [email protected] Wing, Robert F. Ohio State University [email protected] Wittkowski, Markus ESO [email protected] Woitke, Peter Sterrewacht Leiden [email protected] Wood, Peter Australian National University, Mount Stromlo Observatory [email protected] Zamora, Olga Universidad de Granada [email protected] Zhukovska, Svilana Institute of Theoretic Astrophysic, ZAH [email protected]

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Sponsors

The conference organisers gratefully acknowledge the support of the following sponsors.

THE ROBERT F. WING SUPPORT FUND AT OHIO STATE UNIVERSITY

THE AUSTRIAN ACADEMY OF SCIENCES

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