Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488)

J. Kemmer, S. Stock, D. Kossakowski, A. Kaminski, K. Molaverdikhani, M. Schlecker, J. A. Caballero, P. J. Amado, N. Astudillo-Defru, X. Bonfils, D. Ciardi, K. A. Collins, N. Espinoza, A. Fukui, T. Hirano, J. M. Jenkins, D. W. Latham, E. C. Matthews, N. Narita, E. PalléH. Parviainen, A. Quirrenbach, A. Reiners, I. Ribas, G. Ricker, J. E. Schlieder, S. Seager, R. Vanderspek, J. N. Winn, J. M. Almenara, V. J.S. Béjar, P. Bluhm, F. Bouchy, P. Boyd, J. L. Christiansen, C. Cifuentes, R. Cloutier, K. I. Collins, M. Cortés-Contreras, I. J.M. Crossfield, N. Crouzet, J. P. De Leon, D. D. Della-Rose, X. Delfosse, S. Dreizler, E. Esparza-Borges, Z. Essack, Th Forveille, P. Figueira, D. Galadí-Enríquez, T. Gan, A. Glidden, E. J. Gonzales, P. Guerra, H. Harakawa, A. P. Hatzes, Th Henning, E. Herrero, K. Hodapp, Y. Hori, S. B. Howell, M. Ikoma, K. Isogai, S. V. Jeffers, M. Kürster, K. Kawauchi, T. Kimura, P. Klagyivik, T. Kotani, T. Kurokawa, N. Kusakabe, M. Kuzuhara, M. Lafarga, J. H. Livingston, R. Luque, R. Matson, J. C. Morales, M. Mori, P. S. Muirhead, F. Murgas, J. Nishikawa, T. Nishiumi, M. Omiya, S. Reffert, C. Rodríguez López, N. C. Santos, P. Schöfer, R. P. Schwarz, B. Shiao, M. Tamura, Y. Terada, J. D. Twicken, A. Ueda, S. Vievard, N. Watanabe, M. Zechmeister

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28 Scopus citations


We present the confirmation and characterisation of GJ 3473 b (G 50-16, TOI-488.01), a hot Earth-sized planet orbiting an M4 dwarf star, whose transiting signal (P = 1.1980035 ± 0.0000018 d) was first detected by the Transiting Exoplanet Survey Satellite (TESS). Through a joint modelling of follow-up radial velocity observations with CARMENES, IRD, and HARPS together with extensive ground-based photometric follow-up observations with LCOGT, MuSCAT, and MuSCAT2, we determined a precise planetary mass, Mb = 1.86 ± 0.30 M·, and radius, Rb = 1.264 ± 0.050 R·. Additionally, we report the discovery of a second, temperate, non-transiting planet in the system, GJ 3473 c, which has a minimum mass, Mc sin i = 7.41 ± 0.91 M·, and orbital period, Pc = 15.509 ± 0.033 d. The inner planet of the system, GJ 3473 b, is one of the hottest transiting Earth-sized planets known thus far, accompanied by a dynamical mass measurement, which makes it a particularly attractive target for thermal emission spectroscopy.

Original languageEnglish (US)
Article numberA236
JournalAstronomy and Astrophysics
StatePublished - Oct 1 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Planetary systems
  • Planets and satellites: detection
  • Stars: individual: G 50-16
  • Stars: late-type
  • Techniques: photometric
  • Techniques: radial velocities


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