In-depth characterization of the Kepler-10 three-planet system with HARPS-N radial velocities and Kepler transit timing variations

Abstract

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; $R_{\mathrm{p}}=1.47{\mathrm{R}}_{\oplus }$) and the long-period sub-Neptune Kepler-10c ($P=45.294$ d; $R_{\mathrm{p}}=2.35{\mathrm{R}}_{\oplus }$), and a non-transiting planet that causes variations in the Kepler-10c transit times. Measurements of the mass of Kepler-10c in the literature have shown disagreement, depending on the radial-velocity dataset and/or the modeling technique used. Here we report on the analysis of almost 300 high-precision radial velocities gathered with the HARPS-N spectrograph at the Telescopio Nazionale Galileo over $\sim 11$~years, and extracted with the YARARA-v2 tool, which corrects for possible systematics and/or low-level activity variations at the spectrum level. To model these radial velocities, we used three different noise models and various numerical techniques, which all converged to the solution: $M_{\mathrm{p},\mathrm{b}}=3.24\pm 0.32{\mathrm{M}}_{\oplus }$ (10$\sigma$) and ${\rho }_{\mathrm{p},\mathrm{b}}=5.54\pm 0.64\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$ for planet b; $M_{\mathrm{p},\mathrm{c}}=11.29\pm 1.24{\mathrm{M}}_{\oplus }$ (9$\sigma$) and ${\rho }_{\mathrm{p},\mathrm{c}}=4.75\pm 0.53\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$ for planet c; and $M_{\mathrm{p},\mathrm{d}}\sin i=12.00\pm 2.15{\mathrm{M}}_{\oplus }$ (6$\sigma$) and $P=151.06\pm 0.48$ d for the non-transiting planet Kepler-10d. This solution is further supported by the analysis of the Kepler-10c transit timing variations and their simultaneous modeling with the HARPS-N radial velocities. While Kepler-10b is consistent with a rocky composition and a small or no iron core, Kepler-10c may be a water world that formed beyond the water snowline and subsequently migrated inward.

arXiv comment15 pages, 11 figures, 5 tables, Astronomy and Astrophysics, in press

References in corpus (89)

• emcee: The MCMC Hammer
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue
• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• The PLATO 2.0 Mission
• Information criteria for astrophysical model selection
• Importance Nested Sampling and the MultiNest Algorithm
• Kepler planets: a tale of evaporation
• The evaporation valley in the Kepler planets
• EXOFAST: A fast exoplanetary fitting suite in IDL
• Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition
• A Closely-Packed System of Low-Mass, Low-Density Planets Transiting Kepler-11
• Growth Model Interpretation of Planet Size Distribution
• The CORALIE survey for southern extra-solar planets VII. Two short-period Saturnian companions to HD108147 and HD168746
• KEPLER's First Rocky Planet: Kepler-10b
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• An asteroseismic view of the radius valley: stripped cores, not born rocky
• Core-powered mass loss and the radius distribution of small exoplanets
• PolyChord: next-generation nested sampling
• The California Planet Survey I. Four New Giant Exoplanets
• A Gaussian process framework for modelling stellar activity signals in radial velocity data
• Sculpting the Valley in the Radius Distribution of Small Exoplanets as a by-product of Planet Formation: The Core-Powered Mass-Loss Mechanism
• Assessing statistical significance of periodogram peaks
• Breaking the Chains: Hot Super-Earth systems from migration and disruption of compact resonant chains
• A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions
• Extracting Planet Mass and Eccentricity From TTV data
• Binning is sinning: morphological light-curve distortions due to finite integration time
• Three types of gamma-ray bursts
• Density, not radius, separates rocky and water-rich small planets orbiting M dwarf stars
• emcee v3: A Python ensemble sampling toolkit for affine-invariant MCMC
• The orbital eccentricity of small planet systems
• A Detailed Model Grid for Solid Planets from 0.1 through 100 Earth Masses
• Transit Least Squares: Optimized transit detection algorithm to search for periodic transits of small planets
• Wotan: Comprehensive time-series de-trending in Python
• PyTransit: Fast and Easy Exoplanet Transit Modelling in Python
• Tidal Evolution of Close-in Planets
• Atmospheres of low-mass planets: the "boil-off"
• The Mass of Kepler-93b and The Composition of Terrestrial Planets
• A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes
• First order resonance overlap and the stability of close two planet systems
• The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet
• Born Dry in the Photo-Evaporation Desert: Kepler's Ultra-Short-Period Planets Formed Water-Poor
• A nearby M star with three transiting super-Earths discovered by K2
• Determining the Mass of Kepler-78b With Nonparametric Gaussian Process Estimation
• How formation time-scales affect the period dependence of the transition between rocky super-Earths and gaseous sub-Neptunes and implications for ${\eta }_{\oplus }$
• On The Origins Of Eccentric Close-in Planets
• A Spectroscopic Analysis of the California-Kepler Survey Sample: I. Stellar Parameters, Planetary Radii and a Slope in the Radius Gap
• Cold Jupiters and improved masses in 38 Kepler and K2 small planet systems from 3661 HARPS-N radial velocities. No excess of cold Jupiters in small planet systems
• A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system
• Gas giant planets as dynamical barriers to inward-migrating super-Earths
• Measurement of planet masses with transit timing variations due to synodic "chopping" effects
• Detecting extrasolar planets from stellar radial velocities using Bayesian evidence
• Kepler-10c, a 2.2-Earth radius transiting planet in a multiple system
• Giant Impact: An Efficient Mechanism for the Devolatilization of Super-Earths
• Homogeneous Analysis of Hot Earths: Masses, Sizes, and Compositions
• The Hunt for Exomoons with Kepler (HEK): V. A Survey of 41 Planetary Candidates for Exomoons
• Radial Velocity Data Analysis with Compressed Sensing Techniques
• YARARA: Significant improvement of RV precision through post-processing of spectral time-series
• The Structure of Exoplanets
• Bayesian priors for the eccentricity of transiting planets
• Majority of water hides deep in the interiors of exoplanets
• TRADES: A new software to derive orbital parameters from observed transit times and radial velocities. Revisiting Kepler-11 and Kepler-9
• On the Feasibility of Intense Radial Velocity Surveys for Earth-twin Discoveries
• Numerical and Analytical Modelling of Transit Time Variations
• Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits
• Revised Masses and Densities of the Planets around Kepler-10
• A Computational Tool to Interpret the Bulk Composition of Solid Exoplanets based on Mass and Radius Measurements
• Accurate parameters of the oldest known rocky-exoplanet hosting system: Kepler-10 revisited
• A fading radius valley towards M-dwarfs, a persistent density valley across stellar types
• Bias and robustness of eccentricity estimates from radial velocity data
• HARPS-N radial velocities confirm the low densities of the Kepler-9 planets
• Dynamics and Transit Variations of Resonant Exoplanets
• Pinning down the mass of Kepler-10c: the importance of sampling and model comparison
• Exoplanet Imitators: A test of stellar activity behavior in radial velocity signals
• Stellar activity correction using PCA decomposition of shells
• Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS
• Efficient modeling of correlated noise I. Statistical significance of periodogram peaks
• Improving exoplanet detection capabilities with the false inclusion probability. Comparison with other detection criteria in the context of radial velocities
• Testing whether a signal is strictly periodic. Application to disentangling planets and stellar activity in radial velocities
• The HARPS search for southern extra-solar planets XLV. Two Neptune mass planets orbiting HD 13808: a study of stellar activity modelling's impact on planet detection
• Forming Iron-rich Planets with Giant Impacts
• A HARPS-N mass for the elusive Kepler-37d: a case study in disentangling stellar activity and planetary signals
• A new dynamical modeling of the WASP-47 system with CHEOPS observations
• Resonant sub-Neptunes are puffier
• An Apodized Kepler Periodogram for Separating Planetary and Stellar Activity Signals
• K2-263b: A 50-day period sub-Neptune with a mass measurement using HARPS-N
• Probing Kepler's hottest small planets via homogeneous search and analysis of optical secondary eclipses and phase variations
• A continuous multiple hypothesis testing framework for optimal exoplanet detection
• Cosmic Hydrogen and Ice Loss Lines

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• The GAPS programme at TNG LXXI. A sub-Neptune suitable for atmospheric characterization in a multiplanet and mutually inclined system orbiting the bright K dwarf TOI-5789 (HIP 99452)
• The GAPS Programme at the TNG: LXX. TOI-5734b: A hot sub-Neptune orbiting a relatively young K dwarf with an Earth-like density
• Mechanisms of Superrotation in Slowly-Rotating and Tidally-Locked Planets