First Byurakan Spectral Survey. Late-Type Stars. Dwarfs

A total of 18 lists of the First Byurakan Survey of Late-Type Stars (FBSLTS) were published between 1990 and 2016. The stars were found on FBS low-dispersion spectral plates. A systematic search and selection were carried out on a surface of ∼16 000deg2 on almost the whole area of the FBS. Since 2007, all FBS low-resolution spectral plates have been digitized. The second version of the “Revised And Updated Catalogue of the First Byurakan Survey of Late-Type Stars”, containing data for 1471 M and C (carbon) stars (130 C-type giants, 1105 M– giants, and 236 M dwarfs) was generated. Among the 236 M dwarfs selected, 176 are new discoveries. The Gaia EDR3 G broad-band magnitudes are in the range 11.3 < G < 17.1. New distance information by Bailer-Jones et al. (2021), which is based on the EDR3 parallaxes are used to estimate the G-band absolute magnitudes for M dwarfs. 9 FBS M dwarfs (out of 176 new discovered) lie within 25pc of the Sun. The object FBS 0909-082 is more distant (r = 780˙pc) M dwarf among the sample considered, for which G-band absolute magnitude M(G)=9.18, M= 0.59MSun, L=0.13597 LSun, and Teff = 3844 K. This object can be classified as M1-M2 subtype dwarf. The nearest object is FBS0250+167, a M7 subtype dwarf with very high proper motion (5.13 arcsec/yr) and is located at 3.83pc from the Sun. The TESS estimated masses lie in the range 0.095(±0.02)M⊙ ≤M≤0.7(±0.1)M⊙ and Teff in the range 4000K < Teff < 2790K for FBSM dwarfs. Color-absolute magnitude (CaMD) diagrams are constructed for the FBSM dwarfs based on Gaia EDR3 and TESS data.