Densities and Eccentricities of 139 Kepler Planets from Transit Time Variations

Abstract

We extract densities and eccentricities of 139 sub-Jovian planets by analyzing transit time variations (TTVs) obtained by the Kepler mission through Quarter 12. We partially circumvent the degeneracies that plague TTV inversion with the help of an analytical formula for the TTV. From the observed TTV phases, we find that most of these planets have eccentricities of order a few percent. More precisely, the r.m.s. eccentricity is 0.018^{+0.005}_{-0.004}, and planets smaller than 2.5R_\earth are around twice as eccentric as those bigger than 2.5R_\earth. We also find a best-fit density-radius relationship ρ~3 g/cm^3 \times (R/3R_\earth)^{-2.3} for the 56 planets that likely have small eccentricity and hence small statistical correction to their masses. Many planets larger than 2.5R_\earth are less dense than water, implying that their radii are largely set by a massive hydrogen atmosphere.

8 pages, 7 figures, 2 tables; accepted to ApJ; Improved figures and data analysis; Tables 1 and 2 available in ancillary data and from https://sites.google.com/a/u.northwestern.edu/shadden/ttvs

References in corpus (9)

• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• The Mass-Radius Relation for 65 Exoplanets Smaller than 4 Earth Radii
• KEPLER's First Rocky Planet: Kepler-10b
• Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets
• Revised Stellar Properties of Kepler Targets for the Quarter 1-16 Transit Detection Run
• Ocean Planet or Thick Atmosphere: On the Mass-Radius Relationship for Solid Exoplanets with Massive Atmospheres
• Spectro-Thermometry of M dwarfs and their candidate planets: too hot, too cool, or just right?
• Transit Timing Variation of Near-Resonance Planetary Pairs. II. Confirmation of 30 planets in 15 Multiple Planet Systems
• Characterizing the Orbital Eccentricities of Transiting Extrasolar Planets with Photometric Observations

Cited by in corpus (173)

• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• The PLATO 2.0 Mission
• The evaporation valley in the Kepler planets
• Eccentricity from transit photometry: small planets in Kepler multi-planet systems have low eccentricities
• Atmospheric Escape and the Evolution of Close-in Exoplanets
• Breeding Super-Earths and Birthing Super-Puffs in Transitional Disks
• SOPHIE velocimetry of Kepler transit candidates XVII. The physical properties of giant exoplanets within 400 days of period
• The orbital eccentricity of small planet systems
• Exploring Exoplanet Populations with NASA's Kepler Mission
• Revisited Mass-Radius relations for exoplanets below 120 Earth masses
• Exoplanet Orbital Eccentricities Derived From LAMOST-Kepler Analysis
• To Cool is to Accrete: Analytic Scalings for Nebular Accretion of Planetary Atmospheres
• Exoplanet Statistics and Theoretical Implications
• Atmospheres of low-mass planets: the "boil-off"
• Kepler Planet Masses and Eccentricities from TTV Analysis
• Exoplanetary Atmospheres - Chemistry, Formation Conditions, and Habitability
• Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b
• Warm Jupiters are less lonely than hot Jupiters: close neighbours
• Transit Timing Observations from Kepler. IX. Catalog of the Full Long-Cadence Data Set
• A Statistical Reconstruction of the Planet Population Around Kepler Solar-Type Stars
• Four newborn planets transiting the young solar analog V1298 Tau
• Zodiacal Exoplanets in Time (ZEIT) IV: seven transiting planets in the Praesepe cluster
• Secure TTV Mass Measurements: Ten Kepler Exoplanets between 3 and 8 Earth Masses with Diverse Densities and Incident Fluxes
• Atmosphere-interior exchange on hot rocky exoplanets
• The L 98-59 System: Three Transiting, Terrestrial-Sized Planets Orbiting a Nearby M-dwarf
• A Dynamical Analysis of the Kepler-80 System of Five Transiting Planets
• The mass of the Mars-sized exoplanet Kepler-138 b from transit timing
• Architectures of Exoplanetary Systems. I: A Clustered Forward Model for Exoplanetary Systems around Kepler's FGK Stars
• TESS's first planet: a super-Earth transiting the naked-eye star $\pi$ Mensae
• Hydrodynamics of embedded planets' first atmospheres - III. The role of radiation transport for super-Earth planets
• The period ratio distribution of Kepler's candidate multiplanet systems
• Photoevaporation vs. core-powered mass-loss: model comparison with the 3D radius gap
• Habitability of Terrestrial-Mass Planets in the HZ of M Dwarfs. I. H/He-Dominated Atmospheres
• The discoveries of WASP-91b, WASP-105b and WASP-107b: two warm Jupiters and a planet in the transition region between ice giants and gas giants
• Advances in exoplanet science from Kepler
• A reassessment of the in situ formation of close-in super-Earths
• Planetesimal Interactions Can Explain the Mysterious Period Ratios of Small Near-Resonant Planets
• Conclusive evidence for a population of water-worlds around M-dwarfs remains elusive
• Occurrence and core-envelope structure of 1--4x Earth-size planets around Sun-like stars
• A Metallicity Recipe for Rocky Planets
• Architectures of Exoplanetary Systems. III: Eccentricity and Mutual Inclination Distributions of AMD-stable Planetary Systems
• Correlations between compositions and orbits established by the giant impact era of planet formation
• Zodiacal Exoplanets in Time (ZEIT) VI: a three-planet system in the Hyades cluster including an Earth-sized planet
• The statistical mechanics of planet orbits
• Primordial Radius Gap and Potentially Broad Core Mass Distributions of Super-Earths and Sub-Neptunes
• Testing exoplanet evaporation with multi-transiting systems
• Transit timing to first order in eccentricity
• Characterization of the L 98-59 multi-planetary system with HARPS: two confirmed terrestrial planets and a mass upper limit on the third
• TOI-1136 is a Young, Coplanar, Aligned Planetary System in a Pristine Resonant Chain
• Diffuser-Assisted Infrared Transit Photometry for Four Dynamically Interacting \textit{Kepler} Systems
• Properties and occurrence rates of $Kepler$ exoplanet candidates as a function of host star metallicity from the DR25 catalog
• Hydrogen dominated atmospheres on terrestrial mass planets: evidence, origin and evolution
• The Compositional Diversity of Low-Mass Exoplanets
• Architectures of Planetary Systems and Implications for their Formation
• The Densities of Planets in Multiple Stellar Systems
• Numerical and Analytical Modelling of Transit Time Variations
• ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b
• Architectures of Compact Super-Earth Systems Shaped by Instabilities
• Predicting Exoplanets Mass and Radius: A Nonparametric Approach
• Spitzer Secondary Eclipse Observations of Five Cool Gas Giant Planets and Empirical Trends in Cool Planet Emission Spectra
• Mass-Radius relationship for M dwarf exoplanets: Comparing nonparametric and parametric methods
• An Overabundance of Low-density Neptune-like Planets
• Tidal Inflation Reconciles Low-Density Sub-Saturns with Core Accretion
• The Kepler Giant Planet Search. I: A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory
• Exploring Whether Super-Puffs Can Be Explained as Ringed Exoplanets
• The TESS-Keck Survey XX: 15 New TESS Planets and a Uniform RV Analysis of all Survey Targets
• A Compact Multi-Planet System With A Significantly Misaligned Ultra Short Period Planet
• Stellar ages, masses and radii from asteroseismic modeling are robust to systematic errors in spectroscopy
• The Albedos of Kepler's Close-in super-Earths
• One of the closest exoplanet pairs to the 3:2 Mean Motion Resonance: K2-19b \& c
• The unseen planets of double belt debris disk systems
• Long-Period Giant Companions to Three Compact, Multiplanet Systems
• Constraining the entropy of formation from young transiting planets
• Dynamics and Formation of the Near-Resonant K2-24 System: Insights from Transit-Timing Variations and Radial Velocities
• The Eccentricity Distribution of Short-Period Planet Candidates Detected by Kepler in Occultation
• K2-66b and K2-106b: Two extremely hot sub-Neptune-size planets with high densities
• Measuring the Galactic Distribution of Transiting Planets with WFIRST
• An unusually low-density super-Earth transiting the bright early-type M-dwarf GJ 1018 (TOI-244)
• Near-resonance in a system of sub-Neptunes from TESS
• Tides Alone Cannot Explain Kepler Planets Close to 2:1 MMR
• Caught in the Act: Core-powered Mass-loss Predictions for Observing Atmospheric Escape
• An upper boundary in the mass-metallicity plane of exo-Neptunes
• Sub-Neptune Formation: The View from Resonant Planets
• Forming Diverse Super-Earth Systems in Situ
• Formation of compact systems of super-Earths via dynamical instabilities and giant impacts
• Shallower radius valley around low-mass hosts: Evidence for icy planets, collisions or high-energy radiation scatter
• Mass, Density, and Formation Constraints in the Compact, Sub-Earth Kepler-444 System including Two Mars-Mass Planets
• A System of Three Super Earths Transiting the Late K-Dwarf GJ 9827 at Thirty Parsecs
• A spectral approach to transit timing variations
• Oscillations of Relative Inclination Angles in Compact Extrasolar Planetary Systems
• Discovery and Validation of a High-Density sub-Neptune from the K2 Mission
• K2-146: Discovery of Planet c, Precise Masses from Transit Timing, and Observed Precession
• The initial physical conditions of Kepler-36 b & c
• Torque on an exoplanet from an anisotropic evaporative wind
• Frequency of Close Companions among Kepler Planets - a TTV study
• Dynamical instabilities in systems of multiple short-period planets are likely driven by secular chaos: a case study of Kepler-102
• The mass-radius relation of intermediate-mass planets outlined by hydrodynamic escape and thermal evolution
• Spin evolution of Earth-sized exoplanets, including atmospheric tides and core-mantle friction
• The role of dissipative evolution for three-planet, near-resonant extrasolar systems
• Science Extraction from TESS Observations of Known Exoplanet Hosts
• Scaling K2. IV. A Uniform Planet Sample for Campaigns 1-8 and 10-18
• Fundamental limits from chaos on instability time predictions in compact planetary systems
• Stability Boundaries for Resonant Migrating Planet Pairs
• Three small planets transiting the bright young field star K2-233
• A HARPS-N mass for the elusive Kepler-37d: a case study in disentangling stellar activity and planetary signals
• Intra-system uniformity: a natural outcome of dynamical sculpting
• An accurate mass determination for Kepler-1655b, a moderately-irradiated world with a significant volatile envelope
• Formation of Close-in Super-Earths by Giant Impacts: Effects of Initial Eccentricities and Inclinations of Protoplanets
• Earths in Other Solar Systems N-body simulations: the Role of Orbital Damping in Reproducing the Kepler Planetary Systems
• Prospects for TTV Detection and Dynamical Constraints with TESS
• Dynamics and Origins of the Near-Resonant Kepler Planets
• Proximity of exoplanets to first-order mean-motion resonances
• Following up the Kepler field: Masses of Targets for transit timing and atmospheric characterization
• Average Albedos of Close-in Super-Earths and Neptunes from Statistical Analysis of Long Cadence Kepler Secondary Eclipse Data
• Kepler Object of Interest Network I. First results combining ground and space-based observations of Kepler systems with transit timing variations
• Confirming the 3:2 Resonance Chain of K2-138
• Transit Probabilities in Secularly Evolving Planetary Systems
• Exciting the TTV Phases of Resonant Sub-Neptunes
• Two Super-Earths in the 3:2 MMR around KOI-1599
• A Tidal Origin for a 3-body Resonance in Kepler-221
• A Simplified Photodynamical Model for Planetary Mass Determination in Low-Eccentricity Multi-Transiting Systems
• Modal Decomposition of TTV - Inferring Planet Masses and Eccentricities
• TESS Observations of Kepler systems with Transit Timing Variations
• Stability Constrained Characterization of Multiplanet Systems
• The origin and 9:7 MMR dynamics of the Kepler-29 system
• Updated Catalog of Kepler Planet Candidates: Focus on Accuracy and Orbital Periods
• Dynamical Evolution of Closely Packed Multiple Planetary Systems Subject to Atmospheric Mass-Loss
• A Flat Inner Disk Model as an Alternative to the Kepler Dichotomy in the Q1 to Q16 Planet Population
• The TESS-Keck Survey. VI. Two Eccentric sub-Neptunes Orbiting HIP-97166
• On the Orbital Spacing Pattern of Kepler Multiple Planet Systems
• A search for transit timing variations within the exomoon corridor using Kepler data
• Trapping (sub-)Neptunes similar to TOI-216b at the inner disk rim: Implications for the disk viscosity and the Neptunian desert
• Dynamics and Collisional Evolution of Closely Packed Planetary Systems
• Photodynamical analysis of the nearly resonant planetary system WASP-148: Accurate transit-timing variations and mutual orbital inclination
• In Situ and Ex Situ Formation Models of Kepler 11 Planets
• Architecture Classification for Extrasolar Planetary Systems
• Absence of extended atmospheres in low-mass star radius-gap planets GJ 9827 b, GJ 9827 d and TOI-1235 b
• Synergies between Asteroseismology and Exoplanetary Science
• Another super-dense sub-Neptune in K2-182 b and refined mass measurements for K2-199 b and c
• Physical Properties and Impact Parameter Variations of Kepler Planets from Analytic Light Curve Modeling
• A Quantitative Comparison of Exoplanet Catalogs
• A Gap in the Mass Distribution for Warm Neptune and Terrestrial Planets
• Planetary Orbit Eccentricity Trends (POET). I. The Eccentricity-Metallicity Trend for Small Planets Revealed by the LAMOST-Gaia-Kepler Sample
• Residual Gas & Dust Around Transition Objects and Weak T Tauri Stars
• Similarity indexing of exoplanets in search for potential habitability: application to Mars-like worlds
• A close outer companion to the ultra-hot Jupiter TOI-2109 b?
• On the origin of the eccentricity dichotomy displayed by compact super-Earths: dynamical heating by cold giants
• Periodic orbits in the 1:2:3 resonant chain and their impact on the orbital dynamics of the Kepler-51 planetary system
• Unveiling the Planet Population at Birth
• TOI-712: a system of adolescent mini-Neptunes extending to the habitable zone
• TOI-4336 A b: A temperate sub-Neptune ripe for atmospheric characterization in a nearby triple M-dwarf system
• Revisiting the Architecture of the KOI-89 System
• Exploiting periodic orbits as dynamical clues for Kepler and K2 systems
• Hiding Planets Near and Far: The Parameter Space of Hidden Companions for Known Planetary Systems
• A hot mini-Neptune and a temperate, highly eccentric sub-Saturn around the bright K-dwarf TOI-2134
• Estimating Planetary Mass with Deep Learning
• Period Ratio Sculpting Near Second-Order Mean-Motion Resonances
• exoMMR: a New Python Package to Confirm and Characterize Mean Motion Resonances
• Planet Occurrence: Doppler and Transit Surveys
• Can Rocky Exoplanets with Rings Pose as Sub-Neptunes?
• A periodic configuration of the Kepler-25 planetary system?
• Can metal-rich worlds form by giant impacts?
• Predicting exoplanet mass from radius and incident flux: A Bayesian mixture model
• Kepler Object of Interest Network III. Kepler-82f: A new non-transiting $21 M_\bigoplus$ planet from photodynamical modelling
• Forming rocky exoplanets around K-dwarf stars
• Planets similar in size are often dissimilar in interior
• On the 9:7 Mean Motion Resonance Capture in a System of Two Equal-mass Super-Earths
• Earth Similarity Index and Habitability Studies of Exoplanets
• Global Instability of Exo-Moon System Triggered by Photo-Evaporation
• Mass Upper Bounds for Over 50 Kepler Planets Using Low-S/N Transit Timing Variations
• A Validated Low-to-Intermediate Mass Planetary Interior Structure Model and New Mass-Radius Relations
• The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution
• Constraining stellar rotation and planetary atmospheric evolution of a dozen systems hosting sub-Neptunes and super-Earths