Threshold radii of volatile-rich planets
arXiv:1808.09872 · doi:10.3847/1538-4357/aadd09
Abstract
Constraining the planetary composition is essential for exoplanetary characterization. In this paper, we use a statistical analysis to determine the characteristic maximum (threshold) radii for various compositions for exoplanets with masses up to 25 Earth masses (M). We confirm that most planets with radii larger than 1.6 Earth radius (R) are not rocky, and must consist of lighter elements, as found by previous studies. We find that planets with radii above 2.6 R cannot be pure-water worlds, and must contain significant amounts of hydrogen and helium (H-He). We find that planets with radii larger than about 3 R, 3.6 R, and 4.3 R are expected to consist of 2%, 5% and 10% of H-He, respectively. We investigate the sensitivity of the results to the assumed internal structure, the planetary temperature and albedo, and the accuracy of the mass and radius determination. We show that the envelope's metallicity, the percentage of H-He and the distribution of the elements play a significant role in the determination of the threshold radius. Finally, we conclude that despite the degenerate nature of the problem, it is possible to put limits on the possible range of compositions for planets with well-measured mass and radius.
References in corpus (28)
- The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
- The PLATO 2.0 Mission
- Mass-Radius Relationships for Solid Exoplanets
- Most 1.6 Earth-Radius Planets are not Rocky
- The evaporation valley in the Kepler planets
- Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition
- The Mass-Radius Relation for 65 Exoplanets Smaller than 4 Earth Radii
- On the radiative equilibrium of irradiated planetary atmospheres
- An asteroseismic view of the radius valley: stripped cores, not born rocky
- Mass-Radius Relation for Rocky Planets based on PREM
- Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
- Can we constrain interior structure of rocky exoplanets from mass and radius measurements?
- A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions
- Structure and evolution of super-Earth to super-Jupiter exoplanets: I. heavy element enrichment in the interior
- Interior Models of Uranus and Neptune
- A Detailed Model Grid for Solid Planets from 0.1 through 100 Earth Masses
- Ocean Planet or Thick Atmosphere: On the Mass-Radius Relationship for Solid Exoplanets with Massive Atmospheres
- A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes
- Minimum Radii of Super-Earths: Constraints from Giant Impacts
- Mass-radius relationships for exoplanets
- Planet formation with envelope enrichment: new insights on planetary diversity
- The Effect of Composition on the Evolution of Giant and Intermediate-Mass Planets
- Critical core mass for enriched envelopes: the role of H2O condensation
- How cores grow by pebble accretion I. Direct core growth
- The Evolution and Internal Structure of Jupiter and Saturn with Compositional Gradients
- Birth and fate of hot-Neptune planets
- The formation of mini-Neptunes
- Mass-Radius Relationships for Very Low Mass Gaseous Planets
Cited by in corpus (33)
- Hints for a Turnover at the Snow Line in the Giant Planet Occurrence Rate
- Revisited Mass-Radius relations for exoplanets below 120 Earth masses
- Planetary evolution with atmospheric photoevaporation I. Analytical derivation and numerical study of the evaporation valley and transition from super-Earths to sub-Neptunes
- A remnant planetary core in the hot-Neptune desert
- The mass-radius relation of exoplanets, revisited
- Photochemical hazes in sub-Neptunian atmospheres with focus on GJ 1214 b
- Physical constraints for the evolution of life on exoplanets
- Evidence for the volatile-rich composition of a 1.5- planet
- How planets grow by pebble accretion II: Analytical calculations on the evolution of polluted envelopes
- Impact of the measured parameters of exoplanets on the inferred internal structure
- Susceptibility of planetary atmospheres to mass loss and growth by planetesimal impacts: the impact shoreline
- TOI-269 b: An eccentric sub-Neptune transiting a M2 dwarf revisited with ExTrA
- Setting the Stage: Planet formation and Volatile Delivery
- A sub-Neptune and a non-transiting Neptune-mass companion unveiled by ESPRESSO around the bright late-F dwarf HD 5278 (TOI-130)
- Exoplanet Interior Retrievals: core masses and metallicities from atmospheric abundances
- Characterising Atmospheres of Cloudy Temperate Mini-Neptunes with JWST
- Internal water storage capacity of terrestrial planets and the effect of hydration on the M-R relation
- Ariel Planetary Interiors White Paper
- GJ 3090 b: one of the most favourable mini-Neptune for atmospheric characterisation
- The GAPS Programme at TNG XL: A puffy and warm Neptune-sized planet and an outer Neptune-mass candidate orbiting the solar-type star TOI-1422
- Why do more massive stars host larger planets?
- TESS and CHEOPS Discover Two Warm Sub-Neptunes Transiting the Bright K-dwarf HD 15906
- Discovery and characterisation of two Neptune-mass planets orbiting HD 212729 with TESS
- Planet Formation
- About the loss of a primordial atmosphere of super-Earths by planetesimal impacts
- The Effect of Accretion Rate and Composition on the Structure of Ice-rich Super-Earths
- Exploring the habitability and interior composition of exoplanets lying within the extended habitable zone
- The Evolution and Internal Structure of Neptunes and Sub-Neptunes: The importance of thermal conductivity in non-convective regions
- On the Ordering of Exoplanet Systems
- Variations in the Radius Distribution of Single- and Compact Multiple-transiting Planets
- Carbon cycling and habitability of massive Earth-like exoplanets
- On the Need for a Classification System for Consistent Characterization of the Composition of Planetary Bodies
- Stellar chemistry and planet size: insights from GALAH DR4