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

Barragán, O.O.BarragánGandolfi, D.D.GandolfiSmith, A. M. S.A. M. S.SmithDeeg, H. J.H. J.DeegFridlund, M. C. V.M. C. V.FridlundPersson, C. M.C. M.PerssonDonati, P.P.DonatiEndl, M.M.EndlCsizmadia, SzSzCsizmadiaGrziwa, S.S.GrziwaNespral, D.D.NespralHatzes, A. P.A. P.HatzesCochran, W. D.W. D.CochranFossati, L.L.FossatiBrems, S. S.S. S.BremsCabrera, J.J.CabreraCUSANO, FELICEFELICECUSANOEigmüller, PhPhEigmüllerEiroa, C.C.EiroaErikson, A.A.EriksonGuenther, E.E.GuentherKorth, J.J.KorthLorenzo-Oliveira, D.D.Lorenzo-OliveiraMancini, L.L.ManciniPätzold, M.M.PätzoldPrieto-Arranz, J.J.Prieto-ArranzRauer, H.H.RauerRebollido, I.I.RebollidoSaario, J.J.SaarioZakhozhay, O. V.O. V.Zakhozhay2020-10-262020-10-2620180035-8711http://hdl.handle.net/20.500.12386/28009We 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) 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 }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 ∼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.STAMPAenK2-139 b: a low-mass warm Jupiter on a 29-d orbit transiting an active K0 V starArticle10.1093/mnras/stx32072-s2.0-85046107892000427345900023https://academic.oup.com/mnras/article/475/2/1765/47393492018MNRAS.475.1765BFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering