K2-139 b: a low-mass warm Jupiter on a 29-d orbit transiting an active K0 V star. Issue 2 (13th December 2017)

• Record Type: Journal Article
• Authors: Barragán, O; Gandolfi, D; Smith, A M S; Deeg, H J; Fridlund, M C V; Persson, C M; Donati, P; Endl, M; Csizmadia, Sz; Grziwa, S; Nespral, D; Hatzes, A P; Cochran, W D; Fossati, L; Brems, S S; Cabrera, J; Cusano, F; Eigmüller, Ph; Eiroa, C; Erikson, A; Guenther, E; Korth, J; Lorenzo-Oliveira, D; Mancini, L; Pätzold, M; Prieto-Arranz, J; Rauer, H; Rebollido, I; Saario, J; Zakhozhay, O V
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 475:Issue 2(2018)
• Page Start: 1765
• Page End: 1776
• Publication Date: 2017-12-13
• Subjects: planets and satellites: detection -- planets and satellites: individual: K2-139 b (EPIC 218916923b) -- stars: fundamental parameters -- planetary systems; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stx3207
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: 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 (log $R^\prime _\mathrm{HK}$ = −4.46 ± 0.06) K0 V star in K2 Campaign 7. We derive the system's parameters by combining the K2 photometry with ground-based follow-up observations. With a mass of $0.387 _{ - 0.075 } ^ {+ 0.083 }$ 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 −3 can be explained with a core of ∼50 M⊕ . 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.