K2-139 b: a low-mass warm Jupiter on a 29-d orbit transiting an active K0 V star
Journal article, 2018

We announce the discovery of K2-139 b (EPIC 218916923 b), a transiting warm-Jupiter (Teq = 547 ± 25 K) on a 29-d orbit around an active (log R'_HK = -4.46 ± 0.06) K0V 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), K2-139 is an ideal target to measure the spin-orbit angle of a planetary system hosting a warm Jupiter.

planets and satellites: individual: K2-139 b (EPIC 218916923b)

planetary systems

planets and satellites: detection

stars: fundamental parameters


O. Barragán

D. Gandolfi

A. M. S. Smith

H. J. Deeg

Malcolm Fridlund

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Carina Persson

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

P. Donati

M. Endl

Sz. Csizmadia

S. Grziwa

D. Nespral

Artie P. Hatzes

W. D. Cochran

L. Fossati

S. S. Brems

J. Cabrera

F. Cusano

Ph. Eigmüller

C. Eiroa

A. Erikson

E. W. Guenther

J. Korth

D. Lorenzo-Oliveira

L. Mancini

M. Pätzold

J. Prieto-Arranz

H. Rauer

I. Rebollido

J. Saario

O. V. Zakhozhay

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 475 2 1765-1776

Exoplanets from space – CHEOPS and PLATO, ESA’s next two projects

Swedish National Space Board, 2017-01-01 -- 2022-12-31.

Subject Categories

Astronomy, Astrophysics and Cosmology


Basic sciences



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