Gaia Search for stellar Companions of TESS Objects of Interest

TL;DR

This study uses Gaia DR2 data to identify and characterize stellar companions of TESS Objects of Interest, revealing 208 binary and triple systems within 500pc, with diverse companion types and separations.

Contribution

It presents the first Gaia-based survey of stellar companions to TESS targets, providing detailed properties and statistics of these systems.

Findings

Detected 193 binary and 15 triple systems among 1391 stars.

Companions range from 0.08 to 3 solar masses, mostly late K to mid M dwarfs.

Companion separations span from 40 to 9900 AU, with decreasing frequency at larger distances.

Abstract

The first results of a new survey are reported, which explores the 2nd data release of the ESA-Gaia mission, 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 1391 target stars, which are located at distances closer than about 500pc around the Sun. The companions and the targets are equidistant and share a common proper motion, as it is expected for gravitationally bound stellar systems, proven with their accurate Gaia astrometry. The companions exhibit masses in the range between about 0.08$M_\odot$ and 3$M_\odot$ and are most frequently found in the mass range between 0.13 and 0.6$M_{\odot}$. The companions are separated from the targets by about 40 up to 9900au, and their frequency continually decreases with increasing separation. While most of the detected companions are late K to mid M dwarfs, also 5 white dwarf companions were identified in this survey, whose true nature is revealed by their photometric properties.