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Abstract
Post-asymptotic giant branch (AGB) stars are exquisite probes of AGB nucleosynthesis. However, the previous lack of accurate distances jeopardized comparison with theoretical AGB models. The Gaia Early Data Release 3 (Gaia EDR3) has now allowed for a breakthrough in this research landscape. In this study, we focus on a sample of single Galactic post-AGBs for which chemical abundance studies were completed. We combined photometry with geometric distances to carry out a spectral energy distribution (SED) analysis and derive accurate luminosities. We subsequently determined their positions on the Hertzsprung-Russell (HR) diagram and compared this with theoretical post-AGB evolutionary tracks. While most objects are in the post-AGB phase of evolution, we found a subset of low-luminosity objects that are likely to be in the post-horizontal branch phase of evolution, similar to AGB-manqué objects found in globular clusters. Additionally, we also investigated the observed bimodality in the s-process enrichment of Galactic post-AGB single stars of similar Teff and metallicities. This bimodality was expected to be a direct consequence of luminosity with the s-process rich objects having evolved further on the AGB. However, we find that the two populations, the s-process enriched and non-enriched, have similar luminosities (and hence initial masses), revealing an intriguing chemical diversity. For a given initial mass and metallicity, AGB nucleosynthesis appears inhomogeneous and sensitive to other factors, which could be mass loss, along with convective and non-convective mixing mechanisms. Modeling individual objects in detail will be needed to investigate which parameters and processes dominate the photospheric chemical enrichment in these stars.
Original language | English |
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Article number | L13 |
Pages (from-to) | 1-14 |
Number of pages | 14 |
Journal | Astrophysical Journal Letters |
Volume | 927 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Mar 2022 |
Bibliographical note
Copyright © 2022. The Author(s). Published by the American Astronomical Society. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.Fingerprint
Dive into the research topics of 'Luminosities and masses of single Galactic post-asymptotic giant branch stars with distances from Gaia EDR3: The revelation of an s-process diversity'. Together they form a unique fingerprint.Projects
- 1 Finished
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ARC - DECRA: Cosmic Alchemy: Revealing the Origin of Elements in the Universe
19/06/19 → 18/06/22
Project: Other