Know thy star, know thy planet: Chemo-kinematically characterizing TESS targets

TL;DR

This study compiles a comprehensive chemo-kinematic catalogue of over 2.2 million TESS target stars, analyzing their Galactic component memberships and chemical properties to aid exoplanet research.

Contribution

It provides the first large-scale chemo-kinematic characterization of TESS targets, integrating multiple survey data to classify stars by Galactic component and chemical composition.

Findings

Majority of TESS targets are in the thin disc.

4% of targets are in the thick disc.

Less than 1% are in the halo.

Abstract

The Transiting Exoplanet Survey Satellite (TESS) has already begun to discover what will ultimately be thousands of exoplanets around nearby cool bright stars. These potential host stars must be well-understood to accurately characterize exoplanets at the individual and population levels. We present a catalogue of the chemo-kinematic properties of 2,218,434 stars in the TESS Candidate Target List using survey data from Gaia DR2, APOGEE, GALAH, RAVE, LAMOST, and photometrically-derived stellar properties from SkyMapper. We compute kinematic thin disc, thick disc, and halo membership probabilities for these stars and find that though the majority of TESS targets are in the thin disc, 4% of them reside in the thick disc and <1% of them are in the halo. The TESS Objects of Interest in our sample also display similar contributions from the thin disc, thick disc, and halo with a majority of them being in the thin disc. We also explore metallicity and [alpha/Fe] distributions for each Galactic component and show that each cross-matched survey exhibits metallicity and [alpha/Fe] distribution functions that peak from higher to lower metallicity and lower to higher [alpha/Fe] from the thin disc to the halo. This catalogue will be useful to explore planet occurrence rates, among other things, with respect to kinematics, component-membership, metallicity, or [alpha/Fe].