Using HARPS-N to characterize the long-period planets in the PH-2 and Kepler-103 systems

Dubber, Sophie C.Sophie C.DubberMortier, AnneliesAnneliesMortierRice, KenKenRiceNava, ChantanelleChantanelleNavaMalavolta, LucaLucaMalavoltaGiles, HelenHelenGilesCoffinet, AdrienAdrienCoffinetCharbonneau, DavidDavidCharbonneauVanderburg, AndrewAndrewVanderburgBONOMO, ALDO STEFANOALDO STEFANOBONOMOBoschin, WalterWalterBoschinBuchhave, Lars A.Lars A.BuchhaveCollier Cameron, AndrewAndrewCollier CameronCOSENTINO, RosarioRosarioCOSENTINODumusque, XavierXavierDumusqueGhedina, AdrianoAdrianoGhedinaHARUTYUNYAN, AVETAVETHARUTYUNYANHaywood, Raphaëlle D.Raphaëlle D.HaywoodLatham, DavidDavidLathamLópez-Morales, MercedesMercedesLópez-MoralesMICELA, GiuseppinaGiuseppinaMICELAMOLINARI, Emilio CarloEmilio CarloMOLINARIPepe, Francesco A.Francesco A.PepePhillips, DavidDavidPhillipsPiotto, GiampaoloGiampaoloPiottoPORETTI, EnnioEnnioPORETTISasselov, DimitarDimitarSasselovSOZZETTI, AlessandroAlessandroSOZZETTIUdry, StéphaneStéphaneUdry2020-12-152020-12-1520190035-8711http://hdl.handle.net/20.500.12386/28847We present confirmation of the planetary nature of PH-2b, as well as the first mass estimates for the two planets in the Kepler-103 system. PH-2b and Kepler-103c are both long-period and transiting, a sparsely populated category of exoplanets. We use Kepler light-curve data to estimate a radius, and then use HARPS-N radial velocities to determine the semi-amplitude of the stellar reflex motion and, hence, the planet mass. For PH-2b we recover a 3.5σ mass estimate of M_ p = 109^{+30}_{-32} M⊕ and a radius of Rp = 9.49 ± 0.16 R⊕. This means that PH-2b has a Saturn-like bulk density and is the only planet of this type with an orbital period P > 200 d that orbits a single star. We find that Kepler-103b has a mass of M_{p,b} = 11.7^{+4.31}_{-4.72} M⊕ and Kepler-103c has a mass of M_{p,c} = 58.5^{+11.2}_{-11.4} M⊕. These are 2.5σ and 5σ results, respectively. With radii of R_{p,b} = 3.49^{+0.06}_{-0.05} R⊕ and R_{p,c} = 5.45^{+0.18}_{-0.17} R⊕, these results suggest that Kepler-103b has a Neptune-like density, while Kepler-103c is one of the highest density planets with a period P > 100 d. By providing high-precision estimates for the masses of the long-period, intermediate-mass planets PH-2b and Kepler-103c, we increase the sample of long-period planets with known masses and radii, which will improve our understanding of the mass-radius relation across the full range of exoplanet masses and radii.STAMPAenUsing HARPS-N to characterize the long-period planets in the PH-2 and Kepler-103 systemsArticle10.1093/mnras/stz28562-s2.0-85079628965000504000300048https://academic.oup.com/mnras/article/490/4/5103/55865862019MNRAS.490.5103DFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation