Superabundance of Exoplanet Sub-Neptunes Explained by Fugacity Crisis
Abstract
Transiting planets with radii 2-3 R ⊕ are much more numerous than larger planets. We propose that this drop-off is so abrupt because at R ∼ 3 R ⊕ base-of-atmosphere pressure is high enough for the atmosphere to readily dissolve into magma, and this sequestration acts as a strong brake on further growth. The viability of this idea is demonstrated using a simple model. Our results support extensive magma-atmosphere equilibration on sub-Neptunes, with numerous implications for sub-Neptune formation and atmospheric chemistry.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2019
- DOI:
- 10.3847/2041-8213/ab59d9
- arXiv:
- arXiv:1912.02701
- Bibcode:
- 2019ApJ...887L..33K
- Keywords:
-
- Extrasolar rocky planets;
- Exoplanet atmospheres;
- Exoplanet evolution;
- 511;
- 487;
- 491;
- Astrophysics - Earth and Planetary Astrophysics;
- Physics - Geophysics
- E-Print:
- Accepted by Astrophysical Journal Letters