K2-31B, a Grazing Transiting Hot Jupiter on a 1.26-day Orbit around a Bright G7V Star

Grziwa, Sascha; Gandolfi, Davide; Csizmadia, Szilard; Fridlund, Malcolm; Parviainen, Hannu; Deeg, Hans J.; Cabrera, Juan; Djupvik, Amanda A.; Albrecht, Simon; Palle, Enric B.; Pätzold, Martin; Béjar, Victor J. S.; Prieto-Arranz, Jorge; Eigmüller, Philipp; Erikson, Anders; Fynbo, Johan P. U.; Guenther, Eike W.; Hatzes, Artie P.; Kiilerich, Amanda; Korth, Judith; Kuutma, Teet; Montañés-Rodríguez, Pilar; Nespral, David; Nowak, Grzegorz; Rauer, Heike; Saario, Joonas; Sebastian, Daniel; Slumstrup, Ditte
The Astronomical Journal, Volume 152, Issue 5, article id. 132, 5 pp. (2016).


We report the discovery of K2-31b, the first confirmed transiting hot Jupiter detected by the K2 space mission. We combined K2 photometry with FastCam lucky imaging and FIES and HARPS high-resolution spectroscopy to confirm the planetary nature of the transiting object and derived the system parameters. K2-31b is a 1.8-Jupiter-mass planet on a 1.26-day orbit around a G7 V star ({M}\star =0.91 M , {R}\star =0.78 R ). The planetary radius is poorly constrained (0.7 < R p < 1.4 R Jup), owing to the grazing transit and the low sampling rate of the K2 photometry.