Smith, A. M. S.A. M. S.SmithGandolfi, D.D.GandolfiBarragán, O.O.BarragánBowler, B.B.BowlerCsizmadia, Sz.Sz.CsizmadiaEndl, M.M.EndlFridlund, M. C. V.M. C. V.FridlundGrziwa, S.S.GrziwaGuenther, E.E.GuentherHatzes, A. P.A. P.HatzesNowak, G.G.NowakAlbrecht, S.S.AlbrechtAlonso, R.R.AlonsoCabrera, J.J.CabreraCochran, W. D.W. D.CochranDeeg, H. J.H. J.DeegCUSANO, FELICEFELICECUSANOEigmüller, Ph.Ph.EigmüllerErikson, A.A.EriksonHidalgo, D.D.HidalgoHirano, T.T.HiranoJohnson, M. C.M. C.JohnsonKorth, J.J.KorthMann, A.A.MannNarita, N.N.NaritaNespral, D.D.NespralPalle, E.E.PallePätzold, M.M.PätzoldPrieto-Arranz, J.J.Prieto-ArranzRauer, H.H.RauerRibas, I.I.RibasTingley, B.B.TingleyWolthoff, V.V.Wolthoff2020-10-272020-10-2720170035-8711http://hdl.handle.net/20.500.12386/28032We report the discovery from K2 of a transiting planet in an 18.25-d, eccentric (0.19 ± 0.04) orbit around K2-99, an 11th magnitude subgiant in Virgo. We confirm the planetary nature of the companion with radial velocities, and determine that the star is a metal-rich ([Fe/H] = 0.20 ± 0.05) subgiant, with mass 1.60^{+0.14}_{-0.10} M<SUB>☉</SUB> and radius 3.1 ± 0.1 R<SUB>☉</SUB>. The planet has a mass of 0.97 ± 0.09 M<SUB>Jup</SUB> and a radius 1.29 ± 0.05 R<SUB>Jup</SUB>. A measured systemic radial acceleration of -2.12 ± 0.04 ms<SUP>-1</SUP> d<SUP>-1</SUP> offers compelling evidence for the existence of a third body in the system, perhaps a brown dwarf orbiting with a period of several hundred days.STAMPAenArticle10.1093/mnras/stw24872-s2.0-85006354711000393647600016https://academic.oup.com/mnras/article/464/3/2708/24479212017MNRAS.464.2708SFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering