Evaluating Gaia Astrometric Quality and Distances for Galactic Hot Supergiants
Vaidman N.L. Nurmakhametova S.T. Umirova A.B. Khokhlov S.A. Agishev A.T. Yermekbayev B.S.
November 2025Multidisciplinary Digital Publishing Institute (MDPI)
Universe
2025#11Issue 11
Distances to Galactic BA supergiants are essential for determining their luminosities, radii, and positions on the Hertzsprung–Russell diagram, yet Gaia parallaxes for these bright, extended sources are often affected by systematics. We compiled a homogeneous sample of 132 B0–A5 supergiants and re-evaluated their distances using a consistent, quality-controlled approach. Parallaxes from Gaia DR3 and EDR3 were corrected for a magnitude–colour zero-point bias and adjusted for excess noise through RUWE-dependent uncertainty inflation. A Bayesian inference with an exponentially decreasing space–density prior was then applied, adopting the catalogue with the smallest penalised total uncertainty. Distances were accepted only when the corrected parallax signal-to-noise ratio exceeded 2.5, the relative uncertainty was below 40%, and key Gaia quality indicators were nominal. The resulting catalogue delivers robust, quality-vetted distances with realistic uncertainties for each star, providing a reliable foundation for deriving fundamental parameters and for future studies of the flux-weighted gravity–luminosity relation and the evolution of Galactic BA supergiants.
BA supergiants , distance , GAIA , RUWE
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Fesenkov Astrophysical Institute, Observatory, 23, Almaty, 050020, Kazakhstan
Faculty of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi Ave., 71, Almaty, 050040, Kazakhstan
Fesenkov Astrophysical Institute
Faculty of Physics and Technology
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