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...
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...
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...
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...
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...
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....
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...
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...
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...
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...
