Dumusque, XavierBonomo, Aldo S.Haywood, RaphaelleMalavolta, LucaSégransan, DamienBuchhave, Lars A.Cameron, Andrew CollierLatham, DavidMolinari, EmilioPepe, FrancescoUdry, StéphaneCharbonneau, DavidCosentino, RosarioDressing, Courtney DanielleFigueira, PedroFiorenzano, Aldo F. M.Gettel, SaraHarutyunyan, AvetHorne, KeithLopez-Morales, MercedesLovis, ChristopheMayor, MichelMicela, GiusiMotalebi, FatemehNascimbeni, ValerioPhillips, DavidPiotto, GiampaoloPollacco, DonQueloz, DidierRice, KenSasselov, DimitarSozzetti, AlessandroSzentgyorgyi, AndrewWatson, Chris2017-01-172014Dumusque, Xavier, Aldo S. Bonomo, Raphaëlle D. Haywood, Luca Malavolta, Damien Ségransan, Lars A. Buchhave, Andrew Collier Cameron, et al. 2014. “The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet." The Astrophysical Journal 789, no. 2: 154. doi:10.1088/0004-637x/789/2/154.0004-637Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:29991587Kepler-10b was the first rocky planet detected by the Kepler satellite and confirmed with radial velocity follow-up observations from Keck-HIRES. The mass of the planet was measured with a precision of around 30%, which was insufficient to constrain models of its internal structure and composition in detail. In addition to Kepler-10b, a second planet transiting the same star with a period of 45 days was statistically validated, but the radial velocities were only good enough to set an upper limit of 20 M ⊕ for the mass of Kepler-10c. To improve the precision on the mass for planet b, the HARPS-N Collaboration decided to observe Kepler-10 intensively with the HARPS-N spectrograph on the Telescopio Nazionale Galileo on La Palma. In total, 148 high-quality radial-velocity measurements were obtained over two observing seasons. These new data allow us to improve the precision of the mass determination for Kepler-10b to 15%. With a mass of 3.33 ± 0.49 M ⊕ and an updated radius of $1.47^{+0.03}_{-0.02}$ R ⊕, Kepler-10b has a density of 5.8 ± 0.8 g cm–3, very close to the value predicted by models with the same internal structure and composition as the Earth. We were also able to determine a mass for the 45-day period planet Kepler-10c, with an even better precision of 11%. With a mass of 17.2 ± 1.9 M ⊕ and radius of $2.35^{+0.09}_{-0.04}$ R ⊕, Kepler-10c has a density of 7.1 ± 1.0 g cm–3. Kepler-10c appears to be the first strong evidence of a class of more massive solid planets with longer orbital periods.en-USplanetary systemsstars: individual (Kepler-10 KOI-072 KIC 11904151)stars: statisticstechniques: photometrictechniques: spectroscopicJournal Article2017-01-1710.1088/0004-637X/789/2/154