XIV Torino Workshop on AGB stars

Session

Seeds and grains: AGB stars as dust factories in galaxies

13 Jun 2024, 11:30

Sala Gratton (INAF - Observatory of Rome)

70. Studying the wind-driving region of nearby AGB stars with ALMA and SPHERE

Theo Khouri (Chalmers University of Technology)

13/06/2024, 11:30

Talk

Despite many important advances in recent years, we are still unable to predict the dust formation process and the wind-driving mechanism in AGB stars remain impossible to predict from first principles. Particularly, the initial step of dust nucleation and the properties of the grains that drive the outflows in oxygen-rich environments have eluded empirical characterization for a long...

50. ALMA observations of Titanium and Aluminium bearing species in Mira

Maryam Saberi (University of Oslo)

13/06/2024, 11:50

Talk

Asymptotic giant branch (AGB) stars stand out as prominent contributors to the production of dust within our Galaxy. However, the intricate process of inorganic dust grain condensation in the outflows of AGB stars remains uncertain. Theoretical investigations, rooted in chemical and thermal equilibrium, have pinpointed aluminium oxides, titanium oxides, and silicon oxides as the primary...

57. The isotope distributions of presolar SiC grains from carbon-rich asymptotic giant branch stars

Nan Liu (Boston University)

13/06/2024, 12:10

Talk

Presolar grains, microscopic dust formed around various types of stars in their advanced evolutionary stages, recorded intricate details of nucleosynthesis and mixing within their parent stars, offering invaluable insights into diverse stellar processes (Nittler & Ciesla, 2016). Among these, silicon carbide (SiC) stands out as the most extensively studied presolar mineral phase, with the...

7. The Galactic chemical evolution of Mg-isotopic compositions inferred from presolar silicate grains

Peter Hoppe (Max Planck Institute for Chemistry)

13/06/2024, 12:30

Talk

Primitive Solar System materials contain small concentrations of presolar grains that formed in the winds of evolved stars and in the ejecta of stellar explosions [1]. These grains exhibit large isotopic abundance anomalies, the fingerprints of nucleosynthetic and mixing processes in their parent stars, and of Galactic chemical evolution (GCE). Silicates are the most abundant type of presolar...

6. The Synthesis of Organic and Inorganic Compounds in Asymptotic Giant Branch Stars

Sun Kwok (University of British Columbia)

13/06/2024, 14:30

Talk

Infrared and millimeter-wave observations have identified many inorganic and organic molecules in the stellar winds of asymptotic giant branch (AGB) stars. Also synthesized in the outflows are solid-state minerals such as amorphous silicates and refractory oxides. The production of acetylene in extreme carbon stars leads to the formation of benzene and other aromatic and aliphatic compounds in...

14. Laboratory Synthesis of Complex Nanocarbons detected in Carbon-rich Evolved Stars

Prof. Franco Cataldo (Actinium Chemical Research Institute)

13/06/2024, 14:50

Talk

In the laboratory scale it is possible to produce most of the molecular species known (or suspected) to be formed in the evolution from AGBs to PN. These species can be produced through the carbon arc i.e. the electric arc struck between two graphite electrodes. The key reaction product of the carbon arc is the carbon vapor, derived from the sublimation of elemental carbon at T≥4000 K....

52. Temporal changes in the infrared molecular spectrum of a Magellanic carbon star

Greg Sloan (Space Telescope Science Institute)

13/06/2024, 15:10

Talk

The mid-infrared spectrum of a carbon star in the Large Magellanic Cloud (LMC) has changed substantially between a recent observation with the Medium-Resolution Spectrometer (MRS) on the Mid-Infrared Instrument aboard JWST and a spectrum obtained over 18 years ago with the Infrared Spectrograph on the Spitzer Space Telescope. The JWST observation is part of a program to capitalize on the...

77. Dust Production from Metal-Poor AGB Stars: JWST Results from Sextans A

Elizabeth Tarantino (Space Telescope Science Institute)

13/06/2024, 15:30

Talk

Dust formed through the winds from stars on the Asymptotic Giant Branch (AGB) can have a substantial contribution to the overall dust budget in a galaxy. However, it is uncertain how metallicity impacts AGB dust production because model predictions vary and observational constraints are scarce at low metallicity. Quantifying the dust production from very metal poor AGB stars has profound...

75. The intense production of silicates during the final phases of intermediate-mass AGB stars

Ester Marini (Istituto Nazionale di Astrofisica (INAF))

13/06/2024, 16:30

Talk

Silicate dust grains are an important player in the cosmic life cycle of matter and have been detected in a wide variety of environments. Although the intermediate mass stars are regarded as the most efficient manufacturers of silicates in the Universe, the formation process of this dust species in their winds is still highly debated. In this talk I will present our study on a sample of...

26. The impact of dust from AGB stars to the chemical evolution of the ISM

Matthias Maercker (Chalmers University of Technology)

13/06/2024, 16:50

Talk

Asymptotic giant branch (AGB) stars contribute to the chemical evolution of galaxies through the dust grains they release into the interstellar medium (ISM). The detection of pre-solar grains in meteorites shows that at least some of the dust from AGB stars survives the transition into the ISM. It is likely that these grains act as seeds for further dust-growth in the ISM leading to the final...