Searching for GEMS: TOI-6383Ab, a giant planet transiting an M3-dwarf star in a binary system

TL;DR

This paper reports the discovery of a giant planet transiting an M3-dwarf star in a binary system, providing valuable data on GEMS occurrence and characteristics, with implications for planetary formation theories.

Contribution

It presents the detection and confirmation of a new GEMS system around an M-dwarf, expanding the known sample and offering insights into planet formation in low-mass stellar environments.

Findings

Giant planet has a mass of 1.04 M_J and radius of 1.008 R_J.

The host star is an M3-dwarf with a companion star at 3100 AU.

The system supports theories requiring massive, dust-rich protoplanetary discs.

Abstract

We report on the discovery of a transiting giant planet around the 3500 K M3-dwarf star TOI-6383A located 172 pc from Earth. It was detected by the Transiting Exoplanet Survey Satellite (TESS) and confirmed by a combination of ground-based follow-up photometry and precise radial velocity measurements. This planet has an orbital period of $\sim$1.791 days, mass of 1.040$\pm$0.094 $M_J$ and a radius of 1d.008$^{+0.036}_{-0.033} ~R_J$, resulting in a mean bulk density of 1.26$^{+0.18}_{-0.17}$ g cm$^{-3}$. TOI-6383A has an M-dwarf companion star, TOI-6383B, which has a stellar effective temperature $T_{eff}$ $\sim$ 3100 K and a projected orbital separation of 3100 AU. TOI-6383A is a low-mass dwarf star hosting a giant planet and is an intriguing object for planetary evolution studies due to its high planet-to-star mass ratio. This discovery is part of the \textit{Searching for Giant Exoplanets around M-dwarf Stars (GEMS)} Survey, intending to provide robust and accurate estimates of the occurrence of GEMS and the statistics on their physical and orbital parameters. This paper presents an interesting addition to the small number of confirmed GEMS, particularly notable since its formation necessitates massive, ust-rich protoplanetary discs and high accretion efficiency ($>$ 10\%).