Discovery and mass measurement of the hot, transiting, Earth-sized planet, GJ 3929 b
Amado, P. J.; Caballero, J. A.; Pallé, E.; Reiners, A.; Ribas, I.; Quirrenbach, A.; Béjar, V. J. S.; Kaminski, A.; Kürster, M.; Montes, D.; Morales, J. C.; Zechmeister, M.; Passegger, V. M.; Schweitzer, A.; Cortés-Contreras, M.; Dreizler, S.; Jeffers, S. V.; Lafarga, M.; Hatzes, A. P.; Narita, N.; Rodríguez, E.; Henning, Th.; Galadí-Enríquez, D.; Collins, K. A.; Collins, K. I.; Demory, B. -O.; Gillon, M.; Jenkins, J. M.; Luque, R.; Seager, S.; Lillo-Box, J.; Sabin, L.; Molaverdikhani, K.; Latham, D. W.; Ricker, G.; Schwarz, R. P.; Vanderspek, R.; Winn, J.; Fausnaugh, M. M.; McCormac, J.; Fukui, A.; Stock, S.; Herrero, E.; Vanaverbeke, S.; Kemmer, J.; Schlecker, M.; Reffert, S.; Cifuentes, C.; Espinoza, N.; Barclay, T.; Kossakowski, D.; Bluhm, P.; Chaturvedi, P.; Kunimoto, M.; Schöfer, P.; Trifonov, T.; Sota, A.; Tenenbaum, P.; Wells, R.; López-González, M. J.; Gómez Maqueo Chew, Y.; Schanche, N.; Schroffenegger, U.; Huang, C.; Gan, T.; Aceituno, F. J.; Golovin, A.
Germany, Spain, United States, Japan, Switzerland, Mexico, China, Belgium, United Kingdom
Abstract
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.
RV data and stellar activity indices are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/659/A17