부산대학교 도서관

Red dwarf stars, which represent 75% of stars in the Milky Way, can be studied in great detail in the solar neighborhood where the sample is more complete. We intend to better characterize red dwarf candidates selected from the Gaia Catalog of Nearby Stars using optical and near-infrared photometry from the VVVX Survey, DECaPS, Pan-STARRS, and WISE. We performed a cross-matching procedure among the positions of a color-selected sample of M dwarfs in the VVVX Survey and the Gaia EDR3 sub-catalog of nearby stars. We explored their stellar parameters and spectral types using VOSA. Radii were also obtained using the Stefan-Boltzmann equation. Masses and ages were computed for some of the objects using evolutionary tracks and isochrones. Additional mass estimations were obtained with the MKs - M* relation. We then validated our results for the stellar parameters of two of our objects with spectra obtained with the TripleSpec instrument at the SOAR telescope, as well as those of our total amount of stars through a direct comparison with an independent sample from the literature. We revised the objects in our sample and compared their proper motion vectors with other sources within 30" to identify possible companions and probed their RUWE values to identify unresolved companions. We present a catalog of physical parameters for 99 low-mass objects with distances from 43.2 to 111.3 pc. Teffs range from 2500 to 3400 K, with the majority of stars in the sample compatible with being M4 dwarfs. We obtained a good agreement between the stellar parameters computed with VOSA and the estimations from observed spectra, also when comparing with an independent sample from the literature. The distribution of masses obtained with VOSA is concentrated toward the very low-mass regime. Eight objects present values of RUWE >= 1.4 and seven are consistent with being part of a binary system.
Comment: 11 pages, 9 figures