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Title: Mass-radius relations and core-envelope decompositions of super-Earths and sub-Neptunes

Many exoplanets have been discovered with radii of 1-4 R {sub ⊕}, between that of Earth and Neptune. A number of these are known to have densities consistent with solid compositions, while others are 'sub-Neptunes' likely to have significant H{sub 2}-He envelopes. Future surveys will no doubt significantly expand these populations. In order to understand how the measured masses and radii of such planets can inform their structures and compositions, we construct models both for solid layered planets and for planets with solid cores and gaseous envelopes, exploring a range of core masses, H{sub 2}-He envelope masses, and associated envelope entropies. For planets in the super-Earth/sub-Neptune regime for which both radius and mass are measured, we estimate how each is partitioned into a solid core and gaseous envelope, associating a specific core mass and envelope mass with a given exoplanet. We perform this decomposition for both ''Earth-like'' rock-iron cores and pure ice cores, and find that the necessary gaseous envelope masses for this important sub-class of exoplanets must range very widely from zero to many Earth masses, even for a given core mass. This result bears importantly on exoplanet formation and envelope evaporation processes.
Authors:
;  [1] ;  [2]
  1. Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)
  2. Department of Computer Science, Princeton University, Princeton, NJ 08544 (United States)
Publication Date:
OSTI Identifier:
22356741
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DECOMPOSITION; DENSITY; EARTH PLANET; ENTROPY; EVAPORATION; HELIUM; HYDROGEN; ICE; IRON; MASS; MOLECULES; NEPTUNE PLANET; PARTITION; ROCKS; SATELLITE ATMOSPHERES; SATELLITES