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 (Teq = 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 MJ and radius of 0.808 -0.033+0.034 RJ, 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.
- Planetary systems
- Planets and satellites: detection
- Planets and satellites: individual: K2-139 b (EPIC 218916923b)
- Stars: fundamental parameters
- ISSN: 0035-8711