Conveners
Stellar Observations
- Marco Pignatari (Konkoly Observatory, Research Centre for Astronomy and Earth Sciences (CSFK), Hungary)
Stellar Observations
- Marco Pignatari (Konkoly Observatory, Research Centre for Astronomy and Earth Sciences (CSFK), Hungary)
The third early Gaia data release (EDR3) has improved the accuracy of the astrometric parame-
ters of numerous long-period variables (LPVs) stars. Many of these stars are on the Asymptotic
Giant Branch (AGB), showing either a C-rich or O-rich envelope and are characterised by high
luminosity, changing surface composition, and intense mass loss, that make them very useful for
...
IRC+10216 is the archetypal carbon-rich AGB star situated at a mere distance of 130 pc. The star exhibits a high mass loss rate of 2 – 4 x 10-5 M☉ / yr. Until now ~90 molecular species are found in the circumstellar envelope (CSE) of this star alone. The carbonaceous atmosphere around the star shows intense emission of the CO molecule. Guelin et al. (2018) mapped this environment successfully...
Open clusters appear as simple objects in many aspects, with a high degree of homogeneity in their (initial) chemical composition, and the typical solar-scaled abundance pattern for the majority of the chemical species. The striking singularity is represented by heavy elements produced from the slow neutron-capture process reactions. In particular, young open clusters (ages less than a few...
The foundations of stellar nucleosynthesis have been established more than 70 years ago and since then, many progresses have taken place, in particular concerning the heavy-element nucleosynthesis in late stages of the evolution of solar-mass stars. Targeting key-elements, including radio-isotopes, in both intrinsic and extrinsic stars, the latter constituting "cold cases" and useful probes of...
The chemical evolution of galaxies is governed by the chemical yields from stars, especially from Asymptotic Giant Branch (AGB) stars. Post-AGB stars are exquisite probes of AGB nucleosynthesis. Photospheric chemical studies of single post-AGB stars in the Galaxy and the Magellanic Clouds have shown an intriguing chemical diversity that ranges from stars that are extremely enriched in carbon...
Not predicted by stellar evolution theory, observations find that Miras without the 3DUP indicator technetium (Tc) in their atmospheres have a higher near-to-mid IR colours than their Tc-rich siblings (Uttenthaler 2013, A&A 556, A38). Since a near-to-mid IR colour such as K-WISE4 is an indicator of the mass-loss rate of AGB stars, this suggests that the mass-loss rate from post-3DUP Miras is...
A rich zoo of peculiar objects forms when evolved stars with extended and loosely-bound convective envelopes, such as Asymptotic Giant Branch (AGB) stars, undergo gravitational interaction with a binary companion. The stellar, chemical and orbital properties of these peculiar products of binary interactions are essential to understanding the interaction history in such systems and to...
We have discovered an unexpected observational feature of the rare lithium-rich G-K red giants: many have very strong neutral helium 10830 A absorption transitions in their spectra. While over 90% of normal lithium-poor giants have weak He I absorption lines, more than half of the lithium-rich stars have deep, very broad 10830 features. The noble gas helium cannot generate detectable...
The production of the observed cosmic fluorine (F), a highly volatile element, is still shrouded in mystery. While debates rage between the Wolf Rayet stars and the AGBs being the possible sites of F production, a small group of peculiar stars show extreme F overabundances in their atmospheres, further deepening this mystery. These peculiar stars with F overabundances are a group of...
