Phase equilibria of sub-Neptunes and super-Earths

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Young, Edward D., Stixrude, Lars, Rogers, James G., Schlichting, Hilke E., Marcum, Sarah P.
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866909405905158144
author Young, Edward D.
Stixrude, Lars
Rogers, James G.
Schlichting, Hilke E.
Marcum, Sarah P.
author_facet Young, Edward D.
Stixrude, Lars
Rogers, James G.
Schlichting, Hilke E.
Marcum, Sarah P.
contents We investigate the consequences of non-ideal chemical interaction between silicate and overlying hydrogen-rich envelopes for rocky planets using basic tenets of phase equilibria. Based on our current understanding of the temperature and pressure conditions for complete miscibility of silicate and hydrogen, we find that the silicate-hydrogen binary solvus will dictate the nature of atmospheres and internal layering in rocky planets that garnered H$_2$-rich primary atmospheres. The temperatures at the surfaces of supercritical magma oceans will correspond to the silicate-hydrogen solvus. As a result, the radial positions of supercritical magma ocean-atmosphere interfaces, rather than their temperatures and pressures, should reflect the thermal states of these planets. The conditions prescribed by the solvus influence the structure of the atmosphere, and thus the transit radii of sub-Neptunes. Separation of iron-rich metal to form metal cores in sub-Neptunes and super-Earths is not assured due to prospects for neutral buoyancy of metal in silicate melt induced by dissolution of H, Si, and O in the metal at high temperatures.
format Preprint
id arxiv_https___arxiv_org_abs_2408_11321
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Phase equilibria of sub-Neptunes and super-Earths
Young, Edward D.
Stixrude, Lars
Rogers, James G.
Schlichting, Hilke E.
Marcum, Sarah P.
Earth and Planetary Astrophysics
We investigate the consequences of non-ideal chemical interaction between silicate and overlying hydrogen-rich envelopes for rocky planets using basic tenets of phase equilibria. Based on our current understanding of the temperature and pressure conditions for complete miscibility of silicate and hydrogen, we find that the silicate-hydrogen binary solvus will dictate the nature of atmospheres and internal layering in rocky planets that garnered H$_2$-rich primary atmospheres. The temperatures at the surfaces of supercritical magma oceans will correspond to the silicate-hydrogen solvus. As a result, the radial positions of supercritical magma ocean-atmosphere interfaces, rather than their temperatures and pressures, should reflect the thermal states of these planets. The conditions prescribed by the solvus influence the structure of the atmosphere, and thus the transit radii of sub-Neptunes. Separation of iron-rich metal to form metal cores in sub-Neptunes and super-Earths is not assured due to prospects for neutral buoyancy of metal in silicate melt induced by dissolution of H, Si, and O in the metal at high temperatures.
title Phase equilibria of sub-Neptunes and super-Earths
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2408.11321