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

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'(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 similar to 50M circle dot. Given the brightness of the host star (V = 11.653 mag), the relatively short transit duration (similar to 5 h), and the expected amplitude of the Rossiter-McLaughlin effect (similar to 25m s(-1)), K2-139 is an ideal target to measure the spin-orbit angle of a planetary system hosting a warm Jupiter

K2-141 b A 5-M-circle plus super-Earth transiting a K7V star every 6.7 h

We report on the discovery of K2-141 b (EPIC 246393474 b), an ultra-short-period super-Earth on a 6.7 h orbit transiting an active K7V star based on data from K2 campaign 12. We confirmed the planet's existence and measured its mass with a series of follow-up observations: seeing-limited MuSCAT imaging, NESSI high-resolution speckle observations, and FIES and HARPS high-precision radial-velocity monitoring. K2-141 b has a mass of 5.31 +/- 0.46 M-circle plus and radius of 1.54(-0.09)(+0.10), yielding a mean density of 8.00(-1.45)(+1.83) g cm(-3) and suggesting a rocky-iron composition. Models indicate that iron cannot exceed similar to 70% of the total mass. With an orbital period of only 6.7 h, K2-141 b is the shortest-period planet known to date with a precisely determined mass

Detection and characterization of an ultra-dense sub-Neptunian planet orbiting the Sun-like star K2-292

We present the discovery and characterization of a new transiting planet from Campaign 17 of the Kepler extended mission K2. The planet K2-292 b is a warm sub-Neptune on a 17 day orbit around a bright (V = 9.9 mag) solar-like G3 V star with a mass and radius of M∗ = 1.00 ± 0.03 MȮ and R∗ = 1.09 ± 0.03 RȮ, respectively. We modeled simultaneously the K2 photometry and CARMENES spectroscopic data and derived a radius of Rp=2.63-0.10+0.12 RȮ and mass of Mp=24.5-4.4+4.4 MȮ, yielding a mean density of ρp=7.4-1.5+1.6 g cm-3, which makes it one of the densest sub-Neptunian planets known to date. We also detected a linear trend in the radial velocities of K2-292 (γRV =-0.40-0.07+0.07 m s-1 d-1) that suggests a long-period companion with a minimum mass on the order of 33 MȮ. If confirmed, it would support a formation scenario of K2-292 b by migration caused by Kozai-Lidov oscillations. © 2019 ESO.Funding for the K2 mission is provided by the NASA Science Mission directorate. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. CARMENES is an instrument for the Centro Astronomico Hispano-Aleman de Calar Alto (CAHA, Almeria, Spain) funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cientificas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium. R.L. has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 713673 and financial support through the >la Caixa> INPhINIT Fellowship Grant for Doctoral studies at Spanish Research Centres of Excellence, >la Caixa> Banking Foundation, Barcelona, Spain. This work is partly financed by the Spanish Ministry of Economics and Competitiveness through grants ESP2013-48391-C4-2-R and AYA2016-79425-C3, and supported by the Japan Society for Promotion of Science (JSPS) KAKENHI Grant Number JP16K17660, JP18H01265 and JP18H05439, and JST PRESTO Grant Number JPMJPR1775. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant agreement no.: DNRF106). K.W.F.L acknowledges the support of the DFG priority program SPP 1992 >Exploring the Diversity of Exoplanets in the Mass-Density Diagram> (RA 714/14-1). M.F. and C.M.P. gratefully acknowledge the support of the Swedish National Space Agency.Peer Reviewe