Gaia search for stellar companions of TESS Objects of Interest

Abstract

The first results of a new survey, which explores the second data release of the ESA-Gaia mission, are reported in order to search for stellar companions of (Community) TESS Objects of Interest and to characterize their properties. In total, 193 binary and 15 hierarchical triple star systems are presented, detected among 1,391 target stars, which are located at distances closer than about 500 pc around the Sun. The companions and the targets are equidistant and share a common proper motion, as is expected for gravitationally bound stellar systems, proven with their accurate Gaia astrometry. The companions exhibit masses in the range between about 0.08 M⊙ and 3M⊙ and are most frequently found in the mass range between 0.13 and 0.6M⊙. The companions are separated from the targets by about 40 up to 9,900 au, and their frequency continually decreases with increasing separation. While most of the detected companions are late K to mid M dwarfs, also five white dwarf companions were identified in this survey, whose true nature is revealed by their photometric properties.