TOI-1801 b: A temperate mini-Neptune around a young M0.5 dwarf
Abstract
We report the discovery, mass, and radius determination of TOI-1801 b, a temperate mini-Neptune around a young M dwarf. TOI-1801 b was observed in TESS sectors 22 and 49, and the alert that this was a TESS planet candidate with a period of 21.3 days went out in April 2020. However, ground-based follow-up observations, including seeing-limited photometry in and outside transit together with precise radial velocity (RV) measurements with CARMENES and HIRES revealed that the true period of the planet is 10.6 days. These observations also allowed us to retrieve a mass of 5.74 1.46 , which together with a radius of 2.08 0.12 , means that TOI-1801 b is most probably composed of water and rock, with an upper limit of 2\% by mass of H in its atmosphere. The stellar rotation period of 16 days is readily detectable in our RV time series and in the ground-based photometry. We derived a likely age of 600--800 Myr for the parent star TOI-1801, which means that TOI-1801 b is the least massive young mini-Neptune with precise mass and radius determinations. Our results suggest that if TOI-1801 b had a larger atmosphere in the past, it must have been removed by some evolutionary mechanism on timescales shorter than 1 Gyr.
Cite
@article{arxiv.2310.10244,
title = {TOI-1801 b: A temperate mini-Neptune around a young M0.5 dwarf},
author = {M. Mallorquín and E. Goffo and E. Pallé and N. Lodieu and V. J. S. Béjar and H. Isaacson and M. R. Zapatero Osorio and S. Dreizler and S. Stock and R. Luque and F. Murgas and L. Peña and J. Sanz-Forcada and G. Morello and D. R. Ciardi and E. Furlan and K. A. Collins and E. Herrero and S. Vanaverbeke and P. Plavchan and N. Narita and A. Schweitzer and M. Pérez-Torres and A. Quirrenbach and J. Kemmer and A. P. Hatzes and A. Howard and M. Schlecker and S. Reffert and E. Nagel and J. C. Morales and J. Orell-Miquel and C. Duque-Arribas and I. Carleo and C. Cifuentes and G. Nowak and I. Ribas and A. Reiners and P. J. Amado and J. A. Caballero and Th. Henning and V. Pinter and J. M. Akana Murphy and C. Beard and S. Blunt and C. L. Brinkman and B. Cale and A. Chontos and K. I. Collins and I. J. M. Crossfield and F. Dai and P. A. Dalba and S. Dufoer and M. El Mufti and N. Espinoza and T. Fetherolf and A. Fukui and S. Giacalone and C. Gnilka and E. Gonzales and S. K. Grunblatt and S. Howell and D. Huber and S. R. Kane and J. P. de León and J. Lubin and M. G. MacDougall and B. Massey and D. Montes and M. Mori and H. Parviainen and V. M. Passegger and A. S. Polanski and P. Robertson and R. P. Schwarz and G. Srdoc and H. M. Tabernero and A. Tanner and E. Turtelboom and J. Van Zandt and L. Weiss and M. Zechmeister},
journal= {arXiv preprint arXiv:2310.10244},
year = {2023}
}
Comments
Accepted in A&A. 29 pages, 21 figures