K2-139 b : A low-mass warm Jupiter on a 29-d orbit transiting an active K0 V star

Summary, in English

We announce the discovery of K2-139 b (EPIC 218916923 b), a transiting warm-Jupiter (T_eq = 547± 25 K) on a 29-d orbit around an active (logR' _HK =-4.46±0.06) K0V star in K2 Campaign 7.We derive the system's parameters by combining the K2 photometry with groundbased follow-up observations. With a mass of 0.387 _-0.033^+0.075 M_J and radius of 0.808 _-0.033^+0.034 R_J, K2-139 b is one of the transiting warm Jupiters with the lowest mass known to date. The planetary mean density of 0.91 _-0.20^+0.24 g cm^-3can be explained with a core of ~50M_⊕. Given the brightness of the host star (V=11.653 mag), the relatively short transit duration (~5 h), and the expected amplitude of the Rossiter-McLaughlin effect (~25m s^-1), K2-139 is an ideal target to measure the spin-orbit angle of a planetary system hosting a warm Jupiter.

• Author: O. Barragán; D. Gandolfi; A. M.S. Smith; H. J. Deeg; M. C.V. Fridlund; C. M. Persson; P. Donati; M. Endl; Sz Csizmadia; S. Grziwa; D. Nespral; A. P. Hatzes; W. D. Cochran; L. Fossati; S. S. Brems; J. Cabrera; F. Cusano; Ph Eigmüller; C. Eiroa; A. Erikson; E. Guenther; J. Korth; D. Lorenzo-Oliveira; L. Mancini; M. Pätzold; J. Prieto-Arranz; H. Rauer; I. Rebollido; J. Saario; O. V. Zakhozhay
• Publishing year: 2018-04-01
• Language: English
• Pages: 1765-1776
• Publication/Series: Monthly Notices of the Royal Astronomical Society
• Volume: 475
• Issue: 2
• Links: http://dx.doi.org/10.1093/mnras/stx3207
• Document type: Journal article
• Publisher: Oxford University Press
• Keywords: Planetary systems; Planets and satellites: detection; Planets and satellites: individual: K2-139 b (EPIC 218916923b); Stars: fundamental parameters
• Status: Published
• ISBN/ISSN/Other: ISSN: 0035-8711