In-depth characterization of the Kepler-10 three-planet system with HARPS-N RVs and Kepler TTVs

• DOI: 10.48550/arxiv.2502.07996
• Publication Date: 2025-02-11
• Authors: A. S. Bonomo; L. Borsato; Vinesh Rajpaul; Li Zeng; M. Damasso; N. C. Hara; M. Cretignier; A. Leleu; N. Unger; X. Dumusque; F. Lienhard; A. Mortier; L. Naponiello; L. Malavolta; A. Sozzetti; David W. Latham; Ken Rice; R. Bongiolatti; Lars A. Buchhave; A. Collier Cameron; A. F. Martínez Fi...; A. Ghedina; R. D. Haywood; G. Lacedelli; A. Massa; F. Pepe; E. Poretti; S. Udry
• Keywords: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics - Solar and Stellar Astrophysics; FOS: Physical sciences; Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics - Earth and Planetary Astrophysics

The old G3V star Kepler-10 is known to host two transiting planets, the ultra-short-period super-Earth Kepler-10b ($P=0.837$ d; $R_{\rm p}=1.47~\rm R_\oplus$) and long-period sub-Neptune Kepler-10c ($P=45.294$ p}=2.35~\rm R_\oplus$), a non-transiting planet causing variations in transit times. Measurements of mass literature have shown disagreement, depending on radial-velocity dataset and/or modeling technique used. Here we report analysis almost 300 high-precision radial velocities gathered with HARPS-N spectrograph at Telescopio Nazionale Galileo over $\sim11$~years, extracted YARARA-v2 tool correcting for possible systematics low-level activity spectrum level. To model these velocities, used three different noise models various numerical techniques, which all converged solution: $M_{\rm p, b}=3.24 \pm 0.32~\rm M_\oplus$ (10$\sigma$) $\rho_{\rm b}=5.54 0.64~\rm g\;cm^{-3}$ b; c}=11.29 1.24~\rm (9$\sigma$) c}=4.75 0.53~\rm c; d}\sin{i}=12.00 2.15~\rm (6$\sigma$) $P=151.06 0.48$ d Kepler-10d. This solution further supported by timing their simultaneous velocities. While consistent rocky composition small or no iron core, may be water world that formed beyond snowline subsequently migrated inward.