Gaia Calibrated UV Luminous Stars in LAMOST

TL;DR

This paper presents a catalog of ultraviolet luminous stars identified using Gaia DR2 data, focusing on stars with significant UV excess, and cross-matching with variable star and binary catalogs to facilitate stellar activity and binary system studies.

Contribution

The study introduces a new catalog of UV luminous stars calibrated with Gaia data, including a large sample with minimized observational biases, and cross-identifies them with variable and binary star catalogs.

Findings

275 FUV luminous stars identified

1774 NUV luminous stars identified

62% and 16% of the sample are RR Lyr and white dwarf binaries

Abstract

We take advantage of the Gaia data release 2 to present 275 and 1,774 ultraviolet luminous stars in the FUV and the NUV. These stars are 5$\sigma$ exceeding the centers of the reference frame that is built with over one million UV stars in the log $g$ vs $T_\textrm{eff}$ diagram. The Galactic extinction is corrected with the 3D dusty map. In order to limit the Lutz-Kelker effect to an insignificant level, we select the stars with the relative uncertainties of the luminosity less than 40% and the trigonometric parallaxes less than 20%. We cross-identified our sample with the catalogs of RR Lyr stars and possible white dwarf main-sequence binaries, and find they compose $\sim$ 62% and $\sim$ 16% of our sample in the FUV and NUV, respectively. This catalog provides a unique sample to study stellar activity, spectrally unresolved compact main-sequence binaries and variable stars.