Barragán, OscarOscarBarragánGrziwa, SaschaSaschaGrziwaGandolfi, DavideDavideGandolfiFridlund, MalcolmMalcolmFridlundEndl, MichaelMichaelEndlDeeg, Hans J.Hans J.DeegCagigal, Manuel P.Manuel P.CagigalLANZA, Antonino FrancescoAntonino FrancescoLANZAPrada Moroni, Pier G.Pier G.Prada MoroniSmith, Alexis M. S.Alexis M. S.SmithKorth, JudithJudithKorthBedell, MeganMeganBedellCabrera, JuanJuanCabreraCochran, William D.William D.CochranCUSANO, FELICEFELICECUSANOCsizmadia, SzilardSzilardCsizmadiaEigmüller, PhilippPhilippEigmüllerErikson, AndersAndersEriksonGuenther, Eike W.Eike W.GuentherHatzes, Artie P.Artie P.HatzesNespral, DavidDavidNespralPätzold, MartinMartinPätzoldPrieto-Arranz, JorgeJorgePrieto-ArranzRauer, HeikeHeikeRauer2020-05-052020-05-0520160004-6256http://hdl.handle.net/20.500.12386/24500We report the discovery of K2-98b (EPIC 211391664b), a transiting Neptune-size planet monitored by the K2 mission during its Campaign 5. We combine the K2 time-series data with ground-based photometric and spectroscopic follow-up observations to confirm the planetary nature of the object and derive its mass, radius, and orbital parameters. K2-98b is a warm Neptune-like planet in a 10 day orbit around a V = 12.2 mag F-type star with M_star = 1.074 ± 0.042 M_sun, R_star = 1.311 (-0.048, +0.083) R_sun, and age of 5.2 (-1.0, +1.2) Gyr. We derive a planetary mass and radius of M_planet = 32.2 ± 8.1 M_earth and R_planet = 4.3 (-0.2, +0.3) R_earth. K2-98b joins the relatively small group of Neptune-size planets whose mass and radius have been derived with a precision better than 25%. We estimate that the planet will be engulfed by its host star in ∼3 Gyr, due to the evolution of the latter toward the red giant branch.STAMPAenArticle10.3847/0004-6256/152/6/1932-s2.0-85009152008000403841000002https://iopscience.iop.org/article/10.3847/0004-6256/152/6/1932016AJ....152..193BFIS/05 - ASTRONOMIA E ASTROFISICAScienze Fisiche Settori ERC (ERC) di riferimento::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_2 Planetary systems sciences