Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization
Abstract
We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq=525+-11 K) with a radius of Rb=1.217+-0.084 Re and an orbital period of Pb=3.93 d. Precise stellar radial velocities from CARMENES and PFS, as well as archival data from HIRES, UVES, and HARPS also display a 3.93-day periodicity, confirming the planetary nature and leading to a planetary mass of Mb=1.84+-0.31 Me. In addition to the radial velocity signal for GJ 357 b, more periodicities are present in the data indicating the presence of two further planets in the system: GJ 357 c, with a minimum mass of Mc=3.40+-0.46 Me in a 9.12 d orbit, and GJ 357 d, with a minimum mass of Md=6.1+-1.0 Me in a 55.7 d orbit inside the habitable zone. The host is relatively inactive and exhibits a photometric rotation period of Prot=78+-2 d. GJ 357 b is to date the second closest transiting planet to the Sun, making it a prime target for further investigations such as transmission spectroscopy. Therefore, GJ 357 b represents one of the best terrestrial planets suitable for atmospheric characterization with the upcoming JWST and ground-based ELTs.
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@article{arxiv.1904.12818,
title = {Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization},
author = {R. Luque and E. Pallé and D. Kossakowski and S. Dreizler and J. Kemmer and N. Espinoza and J. Burt and G. Anglada-Escudé and V. J. S. Béjar and J. A. Caballero and K. A. Collins and K. I. Collins and M. Cortés-Contreras and E. Díez-Alonso and F. Feng and A. Hatzes and C. Hellier and T. Henning and S. V. Jeffers and L. Kaltenegger and M. Kürster and J. Madden and K. Molaverdikhani and D. Montes and N. Narita and G. Nowak and A. Ofir and M. Oshagh and H. Parviainen and A. Quirrenbach and S. Reffert and A. Reiners and C. Rodríguez-López and M. Schlecker and S. Stock and T. Trifonov and J. N. Winn and M. R. Zapatero Osorio and M. Zechmeister and P. J. Amado and D. R. Anderson and N. E. Batalha and F. F. Bauer and P. Bluhm and C. J. Burke and R. P. Butler and D. A. Caldwell and G. Chen and J. D. Crane and D. Dragomir and C. D. Dressing and S. Dynes and J. M. Jenkins and A. Kaminski and H. Klahr and T. Kotani and M. Lafarga and D. W. Latham and P. Lewin and S. McDermott and P. Montañés-Rodríguez and J. C. Morales and F. Murgas and E. Nagel and S. Pedraz and I. Ribas and G. R. Ricker and P. Rowden and S. Seager and S. A. Shectman and M. Tamura and J. Teske and J. D. Twicken and R. Vanderspeck and S. X. Wang and B. Wohler},
journal= {arXiv preprint arXiv:1904.12818},
year = {2019}
}