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 stars in the 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 is underluminous and we identify these with the recently recognised class of post-Red Giant Branch objects thought to be the result of binary evolution.

Accepted for publication in MNRAS Letters on July 31st, 2022. Table 1 will be available as online supplementary material

References in corpus (14)

• The Gaia mission
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Gaia Early Data Release 3: The astrometric solution
• Unresolved stellar companions with Gaia DR2 astrometry
• A spectroscopic atlas of post-AGB stars and planetary nebulae selected from the IRAS Point Source Catalogue
• An evolutionary catalogue of Galactic post-AGB and related objects
• New light on Galactic post-asymptotic giant branch stars. I. First distance catalogue
• Planetary Nebulae in Gaia EDR3: Central Star identification, properties and binarity
• Binary Central Stars of Planetary Nebulae Discovered Through Photometric Variability V: The Central Stars of HaTr 7 and ESO 330-9
• Luminosities and masses of single Galactic Post-Asymptotic Giant Branch (Post-AGB) stars with distances from $Gaia$ EDR3: The revelation of an $s$-process diversity
• Towards a more complete sample of binary central stars of planetary nebulae with Gaia
• Optical/near-infrared observations of the Fried Egg Nebula: Multiple shell ejections on a 100 yr timescale from a massive yellow hypergiant
• The post-common-envelope binary central star of the planetary nebula Ou 5: a doubly-eclipsing post-red-giant-branch system
• Gaia DR 2 data and the evolutionary status of eight high velocity hot post-AGB candidates

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