A census of post-AGB stars in Gaia DR3: evidence for a substantial population of Galactic post-RGB stars
Abstract
This paper presents the first census of Galactic post-asymptotic giant branch (post-AGB) stars in the Hertzsprung-Russell (HR) diagram. We combined Gaia DR3 parallax-based distances with extinction corrected integrated fluxes and derived luminosities for a sample of 185 stars that had been proposed to be post-AGB stars in the literature. The luminosities allow us to create an HR diagram containing the largest number of post-AGB candidate objects to date. A significant fraction of the objects fall outside the typical luminosity range as covered by theoretical evolutionary post-AGB tracks as well as observed for planetary nebula central stars. These include massive evolved supergiants and lower luminosity objects. Here, we highlight the fact that one-third of the post-AGB candidates are underluminous and we identify these with the recently recognized class of post-red giant branch objects thought to be the result of binary evolution.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2022
- DOI:
- 10.1093/mnrasl/slac088
- arXiv:
- arXiv:2208.02832
- Bibcode:
- 2022MNRAS.516L..61O
- Keywords:
-
- parallaxes;
- stars: AGB and post-AGB;
- stars: evolution;
- stars: distances;
- stars: binaries: general;
- stars: Hertzsprung-Russell and colour-magnitude diagrams;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in MNRAS Letters on July 31st, 2022. Table 1 will be available as online supplementary material