The CARMENES search for exoplanets around M dwarfs HD147379 b: A nearby Neptune in the temperate zone of an early-M dwarf

Reiners, A.; Ribas, I.; Zechmeister, M.; Caballero, J. A.; Trifonov, T.; Dreizler, S.; Morales, J. C.; Tal-Or, L.; Lafarga, M.; Quirrenbach, A.; Amado, P. J.; Kaminski, A.; Jeffers, S. V.; Aceituno, J.; Bejar, V. J. S.; Guardia, J.; Guenther, E. W.; Hagen, H. -J.; Montes, D.; Passegger, V. M.; Seifert, W.; Schweitzer, A.; Cortes-Contreras, M.; Abril, M.; Alonso-Floriano, F. J.; Eiff, M. Ammler-von; Antona, R.; Anglada-Escude, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F. F.; Becerril, S.; Benitez, D.; Berdinas, Z. M.; Bergond, G.; Bluemcke, M.; Brinkmoeller, M.; del Burgo, C.; Cano, J.; Vazquez, M. C. Cardenas; Casal, E.; Cifuentes, C.; Claret, A.; Colome, J.; Czesla, S.; Diez-Alonso, E.; Feiz, C.; Fernandez, M.; Ferro, I. M.; Fuhrmeister, B.; Galadi-Enriquez, D.; Garcia-Piquer, A.; Vargas, M. L. Garcia; Gesa, L.; Galera, V. Gomez; Hernandez, J. I. Gonzalez; Gonzalez-Peinado, R.; Groezinger, U.; Grohnert, S.; Guijarro, A.; de Guindos, E.; Gutierrez-Soto, J.; Hatzes

Publicación: ASTRONOMY & ASTROPHYSICS
2018
VL / 609 - BP / - EP /
abstract
We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 (V = 8.9 mag, M = 0.58 +/- 0.08 M-circle dot), a bright M0.0 V star at a distance of 10.7 pc, is found to undergo periodic RV variations with a semi-amplitude of K = 5.1 +/- 0.4 m s(-1) and a period of P = 86.54 +/- 0.06 d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass m(P) sin i = 25 +/- 2 M-circle plus, 1.5 times the mass of Neptune, with an orbital semi-major axis a = 0.32 au and low eccentricity (e < 0.13). HD 147379 b is orbiting inside the temperate zone around the star, where water could exist in liquid form. The RV time-series and various spectroscopic indicators show additional hints of variations at an approximate period of 21.1 d (and its first harmonic), which we attribute to the rotation period of the star.

Access level

Green submitted, Green accepted, Bronze