Work

An All-sky Catalog of 6.5 Million Primary Red Clump Stars from Gaia DR3 XP Spectra

Year: 2026

Type: article

Abstract: Red clump (RC) stars are excellent standard candles for mapping the three-dimensional structure of the Milky Way. We construct an all-sky catalog of 6.5 million primary RC stars using spectroscopic estimates of asteroseismic parameters inferred from Gaia DR3 low-resolution XP spectra. We train a mixture density network (MDN) on a crossmatched sample. The network maps each 343-dimensional corrected XP spectrum to estimates of ΔΠ 1 , the asymptotic period spacing of dipole gravity modes, and Δ ν , the large frequency separation. We select primary RC stars using these two estimates. We release two complementary catalogs defined by different parameter-space cuts and thresholds: a high-purity Tier 1 sample of 532,189 stars with 97% purity and a high-completeness Tier 2 sample of 6,534,931 stars with 86% completeness. Both catalogs cover the full celestial sphere. We provide distances and extinction values for all stars. We obtain a median photometric distance precision of 6% for Tier 1 RC stars. Using the resultant distances, we independently calibrate the Gaia DR3 parallax zero-point offset. The three-dimensional density distribution traced by the Tier 2 sample extends continuously to R ≃ 25 kpc. Both catalogs are publicly available. These catalogs provide a valuable resource for Galactic archaeology, delivering a homogeneous dataset to trace the chemodynamical evolution of the Milky Way and to calibrate models of stellar populations.

Source: The Astrophysical Journal Supplement Series

DOI: 10.3847/1538-4365/aea224

Authors: Zheng Yu, Bingqiu Chen

Institutions: Chuxiong Normal University, Yunnan University

Language: English

Topic: Stellar, planetary, and galactic studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,499