THE MASS OF Kepler-93b AND THE COMPOSITION OF TERRESTRIAL PLANETS

2014/12/30 by Courtney D. Dressing, David Charbonneau, Xavier Dumusque +35 · 230 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Exoplanet #Planet #Planetary mass #Planetary system #Population #RADIUS #Radial velocity #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #Terrestrial planet #astro-ph.EP #astro-ph.SR

paper · pdf · doi:10.1088/0004-637x/800/2/135

published in The Astrophysical Journal 800(2), 135 (IOP Publishing) · 8 pages, 4 figures. Accepted for publication in ApJ

arxiv created 2014/12/30 · openalex publication_date 2015/02/20 · arxiv updated 2015/06/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

Kepler-93b is a 1.478 ± 0.019 R ⊕ planet with a 4.7 day period around a bright ( V = 10.2), astroseismically characterized host star with a mass of 0.911 ± 0.033 M ☉ and a radius of 0.919 ± 0.011 R ☉ . Based on 86 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32 archival Keck/HIRES observations, we present a precise mass estimate of 4.02 ± 0.68 M ⊕ . The corresponding high density of 6.88 ± 1.18 g cm −3 is consistent with a rocky composition of primarily iron and magnesium silicate. We compare Kepler-93b to other dense planets with well-constrained parameters and find that between 1 and 6 M ⊕ , all dense planets including the Earth and Venus are well-described by the same fixed ratio of iron to magnesium silicate. There are as of yet no examples of such planets with masses >6 M ⊕ . All known planets in this mass regime have lower densities requiring significant fractions of volatiles or H/He gas. We also constrain the mass and period of the outer companion in the Kepler-93 system from the long-term radial velocity trend and archival adaptive optics images. As the sample of dense planets with well-constrained masses and radii continues to grow, we will be able to test whether the fixed compositional model found for the seven dense planets considered in this paper extends to the full population of 1–6 M ⊕ planets.

Citations

• Regression and time series model selection in small samples
• Orbital resonances in the inner neptunian system
• ALL SIX PLANETS KNOWN TO ORBIT KEPLER-11 HAVE LOW DENSITIES
• The Derivation, Properties, and Value of Kepler’s Combined Differential Photometric Precision
• TIDALLY HEATED TERRESTRIAL EXOPLANETS: VISCOELASTIC RESPONSE MODELS
• Mass‐Radius Relationships for Solid Exoplanets
• MOST DETECTS TRANSITS OF HD 97658b, A WARM, LIKELY VOLATILE-RICH SUPER-EARTH
• A Detailed Model Grid for Solid Planets from 0.1 through 100 Earth Masses
• Solar System Abundances and Condensation Temperatures of the Elements
• A rocky composition for an Earth-sized exoplanet
• A super-Earth transiting a nearby low-mass star
• CHARACTERISTICS OF PLANETARY CANDIDATES OBSERVED BYKEPLER. II. ANALYSIS OF THE FIRST FOUR MONTHS OF DATA
• Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits
• Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar Densities

Cited by

• Tidally Distorted, Iron-enhanced Exoplanets Closely Orbiting Their Stars
• Searching for the Transit of the Earth-mass Exoplanet Proxima Centauri b in Antarctica: Preliminary Result
• An Excess of Jupiter Analogs in Super-Earth Systems
• Signatures of the core-powered mass-loss mechanism in the exoplanet population: dependence on stellar properties and observational predictions
• Implications of an improved water equation of state for water-rich planets
• The First Habitable-zone Earth-sized Planet from TESS. II. Spitzer Confirms TOI-700 d