Korth, J.J.KorthCsizmadia, SzSzCsizmadiaGandolfi, D.D.GandolfiFridlund, M.M.FridlundPätzold, M.M.PätzoldHirano, T.T.HiranoLivingston, J.J.LivingstonPersson, C. M.C. M.PerssonDeeg, H. J.H. J.DeegJustesen, A. B.A. B.JustesenBarragán, O.O.BarragánGrziwa, S.S.GrziwaEndl, M.M.EndlTronsgaard, R.R.TronsgaardDai, F.F.DaiCochran, W. D.W. D.CochranAlbrecht, S.S.AlbrechtAlonso, R.R.AlonsoCabrera, J.J.CabreraCauley, P. W.P. W.CauleyCUSANO, FELICEFELICECUSANOEigmüller, PhPhEigmüllerErikson, A.A.EriksonEsposito, M.M.EspositoGuenther, E. W.E. W.GuentherHatzes, A. P.A. P.HatzesHidalgo, D.D.HidalgoKuzuhara, M.M.KuzuharaMontañes, P.P.MontañesNAPOLITANO, NICOLA ROSARIONICOLA ROSARIONAPOLITANONarita, N.N.NaritaNiraula, P.P.NiraulaNespral, D.D.NespralNowak, G.G.NowakPalle, E.E.PallePetrillo, C. E.C. E.PetrilloRedfield, S.S.RedfieldPrieto-Arranz, J.J.Prieto-ArranzRauer, H.H.RauerSmith, A. M. S.A. M. S.SmithTORTORA, CRESCENZOCRESCENZOTORTORAVan Eylen, V.V.Van EylenWinn, J. N.J. N.Winn2021-01-042021-01-0420190035-8711http://hdl.handle.net/20.500.12386/29418We report the independent discovery and characterization of two K2 planets: K2-180b, a mini-Neptune-sized planet in an 8.9-d orbit transiting a V = 12.6 mag, metal-poor ([Fe/H] = -0.65 ± 0.10) K2V star in K2 campaign 5; K2-140b, a transiting hot Jupiter in a 6.6-d orbit around a V = 12.6 mag G6V ([Fe/H] = + 0.10 ± 0.10) star in K2 campaign 10. Our results are based on K2 time-series photometry combined with high-spatial resolution imaging and high-precision radial velocity measurements. We present the first mass measurement of K2-180b. K2-180b has a mass of M<SUB>p</SUB> = 11.3 ± 1.9 M_{\oplus} and a radius of R<SUB>p</SUB> = 2.2 ± 0.1 R_{\oplus}, yielding a mean density of ρ<SUB>p</SUB> = 5.6 ± 1.9 g cm<SUP>-3</SUP>, suggesting a rocky composition. Given its radius, K2-180b is above the region of the so-called `planetary radius gap'. K2-180b is in addition not only one of the densest mini-Neptune-sized planets, but also one of the few mini-Neptune-sized planets known to transit a metal-poor star. We also constrain the planetary and orbital parameters of K2-140b and show that, given the currently available Doppler measurements, the eccentricity is consistent with zero, contrary to the results of a previous study.STAMPAenArticle10.1093/mnras/sty27602-s2.0-85057187414000454578700027https://openaccess.inaf.it/retrieve/22416/sty2760.pdf2019MNRAS.482.1807KFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering