Possibilities of habitable zones around post-AGB stars

Abstract

A post-ABG (asymptotic giant branch) star is a very luminous late stage in the evolution of a low-to intermediate mass star. A post-AGB star is found in a specific region on the Hertzsprung-Russell (HR) diagram. The HR diagram compares intrinsic properties of stars based on their surface temperature and luminosity. Specifically, post-AGB stars are bright red giants whose core has shrunk but the star itself has expanded to become this red giant that is surrounded by a dusty envelope. The HR diagram is used to select specific stars based off their properties or stellar evolution. Where would the habitable zone around post-AGB stars be? A habitable zone is the distance of orbits around a star that can support liquid water and therefore would be open to possibilities of life. The distance of the habitable zone depends on the luminosity of the star. To measure that luminosity, we studied the total flux (brightness as measured on Earth) and the distance of a pilot sample of six stars selected from the paper, An evolutionary catalogue of galactic post-AGB and related objects via Vizier (Szczerba et al. 2007).