TOI-3235 b: A Transiting Giant Planet around an M4 Dwarf Star
Abstract
We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry and confirmed with radial velocities from ESPRESSO and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of 0.665 ± 0.025 M J and a radius of 1.017 ± 0.044 R J. It orbits close to its host star, with an orbital period of 2.5926 days but has an equilibrium temperature of ≈ 604 K, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of 0.3939 ± 0.0030 M ⊙, a radius of 0.3697 ± 0.0018 R ⊙, an effective temperature of 3389 K, and a J-band magnitude of 11.706 ± 0.025. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M dwarfs for atmospheric characterization.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2023
- DOI:
- arXiv:
- arXiv:2302.10008
- Bibcode:
- 2023ApJ...946L...4H
- Keywords:
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- Exoplanets;
- Transit photometry;
- Radial velocity;
- M dwarf stars;
- 498;
- 1709;
- 1332;
- 982;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 15 pages, 4 figures. Accepted for publication in APJL