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)

stars: fundamental parameters

planetary systems

planets and satellites: detection

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Published in

Monthly Notices of the Royal Astronomical Society

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

Vol. 475 Issue 2 p. 1765-1776

Research Project(s)

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

Swedish National Space Board (174/18), 2017-01-01 -- 2022-12-31.

Categorizing

Subject Categories (SSIF 2011)

Astronomy, Astrophysics and Cosmology

Roots

Basic sciences

Identifiers

DOI

10.1093/mnras/stx3207

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Latest update

3/16/2025