The Nearby Evolved Stars Survey (NESS) V: properties of volume-limited samples of Galactic evolved stars

TL;DR

This study analyzes the properties, distribution, and characteristics of volume-limited samples of evolved stars in the Solar Neighborhood, highlighting issues with temperature estimates and sampling biases in dust-producing stars.

Contribution

It provides a comprehensive statistical analysis of two complete samples of evolved stars, addressing distance, luminosity, and distribution, and compares observations with stellar evolution models.

Findings

Gaia GSP-Phot temperatures are often underestimated for bright giants.

Literature under-samples extreme dust-producing AGB stars.

Stellar models over-predict AGB stars around 500 Myr.

Abstract

We provide a meta-study of the statistical and individual properties of two volume-complete sets of evolved stars in the Solar Neighbourhood: (1) 852 stars from the Nearby Evolved Stars Survey (NESS), and (2) a partially overlapping set of 507 evolved stars within 300 pc. We also investigate distance determinations to these stars, their luminosity functions and their spatial distribution. Gaia APSIS GSP-Phot AENEAS temperatures of bright giant stars often appear to be underestimated. Existing literature on AGB stars under-samples both the most and least extreme nearby dust-producing stars. We reproduce the literature star-formation history of the solar neighbourhood, though stellar-evolution models over-predict the number of AGB stars of ages around 500 Myr. The distribution of AGB stars broadly matches the known 300 pc scale height of the Galactic disc and shows concentration in the direction of the Galactic centre. Most dust-producing carbon stars belong to the Galactic thick-disc population.