A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS

Huber, DanielDanielHuberChaplin, William J.William J.ChaplinChontos, AshleyAshleyChontosKjeldsen, HansHansKjeldsenChristensen-Dalsgaard, JørgenJørgenChristensen-DalsgaardBedding, Timothy R.Timothy R.BeddingBall, WarrickWarrickBallBrahm, RafaelRafaelBrahmEspinoza, NestorNestorEspinozaHenning, ThomasThomasHenningJordán, AndrésAndrésJordánSarkis, PaulaPaulaSarkisKnudstrup, EmilEmilKnudstrupAlbrecht, SimonSimonAlbrechtGrundahl, FrankFrankGrundahlFredslund Andersen, MadsMadsFredslund AndersenPallé, Pere L.Pere L.PalléCrossfield, IanIanCrossfieldFulton, BenjaminBenjaminFultonHoward, Andrew W.Andrew W.HowardIsaacson, Howard T.Howard T.IsaacsonWeiss, Lauren M.Lauren M.WeissHandberg, RasmusRasmusHandbergLund, Mikkel N.Mikkel N.LundSerenelli, Aldo M.Aldo M.SerenelliRørsted Mosumgaard, JakobJakobRørsted MosumgaardStokholm, AmalieAmalieStokholmBieryla, AllysonAllysonBierylaBuchhave, Lars A.Lars A.BuchhaveLatham, David W.David W.LathamQuinn, Samuel N.Samuel N.QuinnGaidos, EricEricGaidosHirano, TeruyukiTeruyukiHiranoRicker, George R.George R.RickerVanderspek, Roland K.Roland K.VanderspekSeager, SaraSaraSeagerJenkins, Jon M.Jon M.JenkinsWinn, Joshua N.Joshua N.WinnAntia, H. M.H. M.AntiaAppourchaux, ThierryThierryAppourchauxBasu, SarbaniSarbaniBasuBell, Keaton J.Keaton J.BellBenomar, OthmanOthmanBenomarBONANNO, Alfio MaurizioAlfio MaurizioBONANNOBuzasi, Derek L.Derek L.BuzasiCampante, Tiago L.Tiago L.CampanteÇelik Orhan, Z.Z.Çelik OrhanCORSARO, ENRICO MARIA NICOLAENRICO MARIA NICOLACORSAROCunha, Margarida S.Margarida S.CunhaDavies, Guy R.Guy R.DaviesDeheuvels, SebastienSebastienDeheuvelsGrunblatt, Samuel K.Samuel K.GrunblattHasanzadeh, AmirAmirHasanzadehDI MAURO, Maria GiuseppinaMaria GiuseppinaDI MAUROGarcía, Rafael A.Rafael A.GarcíaGaulme, PatrickPatrickGaulmeGIRARDI, Leo AlbertoLeo AlbertoGIRARDIGuzik, Joyce A.Joyce A.GuzikHon, MarcMarcHonJiang, ChenChenJiangKallinger, ThomasThomasKallingerKawaler, Steven D.Steven D.KawalerKuszlewicz, James S.James S.KuszlewiczLebreton, YvelineYvelineLebretonLi, TandaTandaLiLucas, MilesMilesLucasLundkvist, Mia S.Mia S.LundkvistMann, Andrew W.Andrew W.MannMathis, StéphaneStéphaneMathisMathur, SavitaSavitaMathurMazumdar, AnweshAnweshMazumdarMetcalfe, Travis S.Travis S.MetcalfeMIGLIO, ANDREAANDREAMIGLIOMonteiro, Mário J. P. F. G.Mário J. P. F. G.MonteiroMosser, BenoitBenoitMosserNoll, AnthonyAnthonyNollNsamba, BenardBenardNsambaOng, Jia Mian JoelJia Mian JoelOngÖrtel, S.S.ÖrtelPereira, FilipeFilipePereiraRanadive, PriteshPriteshRanadiveRégulo, ClaraClaraRéguloDa Silva Rodrigues, ThaiseThaiseDa Silva RodriguesRoxburgh, Ian W.Ian W.RoxburghSilva Aguirre, VictorVictorSilva AguirreSmalley, BarryBarrySmalleySchofield, MathewMathewSchofieldSousa, Sérgio G.Sérgio G.SousaStassun, Keivan G.Keivan G.StassunStello, DennisDennisStelloTayar, JamieJamieTayarWhite, Timothy R.Timothy R.WhiteVerma, KuldeepKuldeepVermaVrard, MathieuMathieuVrardYıldız, M.M.YıldızBaker, DavidDavidBakerBazot, MichaëlMichaëlBazotBeichmann, CharlesCharlesBeichmannBergmann, ChristophChristophBergmannBugnet, LisaLisaBugnetCale, BrysonBrysonCaleCarlino, RobertoRobertoCarlinoCartwright, Scott M.Scott M.CartwrightChristiansen, Jessie L.Jessie L.ChristiansenCiardi, David R.David R.CiardiCreevey, OrlaghOrlaghCreeveyDittmann, Jason A.Jason A.DittmannDo Nascimento, Jose-Dias, Jr.Jose-Dias, Jr.Do NascimentoVan Eylen, VincentVincentVan EylenFürész, GaborGaborFürészGagné, JonathanJonathanGagnéGao, PeterPeterGaoGazeas, KosmasKosmasGazeasGiddens, FrankFrankGiddensHall, Oliver J.Oliver J.HallHekker, SaskiaSaskiaHekkerIreland, Michael J.Michael J.IrelandLatouf, NatashaNatashaLatoufLeBrun, DannyDannyLeBrunLevine, Alan M.Alan M.LevineMatzko, WilliamWilliamMatzkoNatinsky, EvaEvaNatinskyPage, EmmaEmmaPagePlavchan, PeterPeterPlavchanMansouri-Samani, MasoudMasoudMansouri-SamaniMcCauliff, SeanSeanMcCauliffMullally, Susan E.Susan E.MullallyOrenstein, BrendanBrendanOrensteinGarcia Soto, AylinAylinGarcia SotoPaegert, MartinMartinPaegertvan Saders, Jennifer L.Jennifer L.van SadersSchnaible, ChloeChloeSchnaibleSoderblom, David R.David R.SoderblomSzabó, RóbertRóbertSzabóTanner, AngelleAngelleTannerTinney, C. G.C. G.TinneyTeske, JohannaJohannaTeskeThomas, AlexandraAlexandraThomasTrampedach, RegnerRegnerTrampedachWright, DuncanDuncanWrightYuan, Thomas T.Thomas T.YuanZohrabi, FarzanehFarzanehZohrabi2021-02-172021-02-1720190004-6256http://hdl.handle.net/20.500.12386/30434We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V = 8.2 mag), spectroscopically classified subgiant that oscillates with an average frequency of about 430 μHz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2 minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (R ⋆ = 2.943 ± 0.064 R ☉), mass (M ⋆ = 1.212 ± 0.074 M ☉), and age (4.9 ± 1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a “hot Saturn” (R p = 9.17 ± 0.33 R ⊕) with an orbital period of ∼14.3 days, irradiance of F = 343 ± 24 F ⊕, and moderate mass (M p = 60.5 ± 5.7 M ⊕) and density (ρ p = 0.431 ± 0.062 g cm-3). The properties of HD 221416 b show that the host-star metallicity-planet mass correlation found in sub-Saturns (4-8 R ⊕) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to ∼15%, HD 221416 b is one of the best characterized Saturn-size planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology.STAMPAenA Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESSArticle10.3847/1538-3881/ab14882-s2.0-85072292342000469975500005https://iopscience.iop.org/article/10.3847/1538-3881/ab14882019AJ....157..245HFIS/05 - ASTRONOMIA E ASTROFISICA