Discovery and mass measurement of the hot, transiting, Earth-sized planet, GJ 3929 b

Kemmer, J. and Dreizler, S. and Kossakowski, D. and Stock, S. and Quirrenbach, A. and Caballero, J. A. and Amado, P. J. and Collins, K. A. and Espinoza, N. and Herrero, E. and Jenkins, J. M. and Latham, D. W. and Lillo-Box, J. and Narita, N. and Palle, E. and Reiners, A. and Ribas, I. and Ricker, G. and Rodriguez, E. and Seager, S. and Vanderspek, R. and Wells, R. and Winn, J. and Aceituno, F. J. and Bejar, V. J. S. and Barclay, T. and Bluhm, P. and Chaturvedi, P. and Cifuentes, C. and Collins, K. I. and Cortes-Contreras, M. and Demory, B. -O. and Fausnaugh, M. M. and Fukui, A. and Chew, Y. Gomez Maqueo and Galadi-Enriquez, D. and Gan, T. and Gillon, M. and Golovin, A. and Hatzes, A. P. and Henning, Th. and Huang, C. ORCID: and Jeffers, S. V. and Kaminski, A. and Kunimoto, M. and Kurster, M. and Lopez-Gonzalez, M. J. and Lafarga, M. and Luque, R. and McCormac, J. and Molaverdikhani, K. and Montes, D. and Morales, J. C. and Passegger, V. M. and Reffert, S. and Sabin, L. and Schofer, P. and Schanche, N. and Schlecker, M. and Schroffenegger, U. and Schwarz, R. P. and Schweitzer, A. and Sota, A. and Tenenbaum, P. and Trifonov, T. and Vanaverbeke, S. and Zechmeister, M. (2022) Discovery and mass measurement of the hot, transiting, Earth-sized planet, GJ 3929 b. Astronomy and Astrophysics, 659:A17. pp. 1-23. ISSN 0004-6361


We report the discovery of GJ 3929 b, a hot Earth-sized planet orbiting the nearby M3.5 V dwarf star, GJ 3929 (G 180-18, TOI-2013). Joint modelling of photometric observations from TESS sectors 24 and 25 together with 73 spectroscopic observations from CARMENES and follow-up transit observations from SAINT-EX, LCOGT, and OSN yields a planet radius of Rb = 1.150 ± 0.040 R⊕, a mass of Mb = 1.21 ± 0.42 M⊕, and an orbital period of Pb = 2.6162745 ± 0.0000030 d. The resulting density of ρb = 4.4 ± 1.6 g cm-3 is compatible with the Earth's mean density of about 5.5 g cm-3. Due to the apparent brightness of the host star (J = 8.7 mag) and its small size, GJ 3929 b is a promising target for atmospheric characterisation with the JWST. Additionally, the radial velocity data show evidence for another planet candidate with P[c] = 14.303 ± 0.035 d, which is likely unrelated to the stellar rotation period, Prot = 122 ± 13 d, which we determined from archival HATNet and ASAS-SN photometry combined with newly obtained TJO data.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 04 Apr 2022 02:34
Last Modified: 23 Sep 2022 04:21
Uncontrolled Keywords: Planetary systems; Planets and satellites: Detection; Stars: Individual: GJ 3929; Stars: Late-type; Techniques: Photometric; Techniques: Radial velocities; Astrophysics - Earth and Planetary Astrophysics
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
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