TOI 4201 b and TOI 5344 b: Discovery of Two Transiting Giant Planets Around M Dwarf Stars and Revised Parameters for Three Others

TL;DR

This paper reports the discovery of two new transiting giant planets around M dwarf stars by TESS, updates parameters for three known systems, and discusses a new method for handling systematic errors in stellar models.

Contribution

It presents the discovery of two new giant planets around M dwarfs and introduces a procedure to account for systematic errors in stellar evolution models.

Findings

All five host stars have super-solar metallicities.

Close-in giant planets are more common around metal-rich M dwarfs.

Precise planetary and stellar parameters were measured for six systems.

Abstract

We present the discovery from the TESS mission of two giant planets transiting M dwarf stars: TOI 4201 b and TOI 5344 b. We also provide precise radial velocity measurements and updated system parameters for three other M dwarfs with transiting giant planets: TOI 519, TOI 3629 and TOI 3714. We measure planetary masses of 0.525 +- 0.064 M_J, 0.243 +- 0.020 M_J, 0.689 +- 0.030 M_J, 2.57 +- 0.15 M_J, and 0.412 +- 0.040 M_J for TOI 519 b, TOI 3629 b, TOI 3714 b, TOI 4201 b, and TOI 5344 b, respectively. The corresponding stellar masses are 0.372 +- 0.018 M_s, 0.635 +- 0.032 M_s, 0.522 +- 0.028 M_s, 0.625 +- 0.033 M_s and 0.612 +- 0.034 M_s. All five hosts have super-solar metallicities, providing further support for recent findings that, like for solar-type stars, close-in giant planets are preferentially found around metal-rich M dwarf host stars. Finally, we describe a procedure for accounting for systematic errors in stellar evolution models when those models are included directly in fitting a transiting planet system.