The Fate of Hydrogen and Helium: From Planetary Embryos to Earth- and Neptune-like Worlds

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Gupta, Akash, Luo, Haiyang, Deng, Jie, Burrows, Adam
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866915585093271552
author Gupta, Akash
Luo, Haiyang
Deng, Jie
Burrows, Adam
author_facet Gupta, Akash
Luo, Haiyang
Deng, Jie
Burrows, Adam
contents Hydrogen, helium, silicates, and iron are key building blocks of rocky and gas-rich planets, yet their chemical interactions remain poorly constrained. Using first-principles molecular dynamics and thermodynamic integration, we quantify hydrogen and helium partitioning between molten silicate mantles and metallic cores for Earth-to-Neptune-mass planets. Hydrogen becomes strongly siderophilic above $\sim$25 GPa but weakens beyond $\sim$200 GPa, whereas helium remains lithophilic yet increasingly soluble in metal with pressure. Incorporating these trends into coupled structure-chemistry models suggests that majority of hydrogen and helium reside in planetary interiors, not atmospheres, with abundances strongly depending on planet mass. Such volatile exchange may influence the redox states of secondary atmospheres, longevity of primordial envelopes, predicted CHNOPS abundances, and emergence of helium-enriched atmospheres, while He 1083 nm and H Lyman-$α$ lines provide potential probes of atmosphere-interior exchange. These findings link atomic-scale interactions to planetary-scale observables, providing new constraints on the origins of Earth-to-Neptune-sized worlds.
format Preprint
id arxiv_https___arxiv_org_abs_2510_24956
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Fate of Hydrogen and Helium: From Planetary Embryos to Earth- and Neptune-like Worlds
Gupta, Akash
Luo, Haiyang
Deng, Jie
Burrows, Adam
Earth and Planetary Astrophysics
Materials Science
Atmospheric and Oceanic Physics
Computational Physics
Hydrogen, helium, silicates, and iron are key building blocks of rocky and gas-rich planets, yet their chemical interactions remain poorly constrained. Using first-principles molecular dynamics and thermodynamic integration, we quantify hydrogen and helium partitioning between molten silicate mantles and metallic cores for Earth-to-Neptune-mass planets. Hydrogen becomes strongly siderophilic above $\sim$25 GPa but weakens beyond $\sim$200 GPa, whereas helium remains lithophilic yet increasingly soluble in metal with pressure. Incorporating these trends into coupled structure-chemistry models suggests that majority of hydrogen and helium reside in planetary interiors, not atmospheres, with abundances strongly depending on planet mass. Such volatile exchange may influence the redox states of secondary atmospheres, longevity of primordial envelopes, predicted CHNOPS abundances, and emergence of helium-enriched atmospheres, while He 1083 nm and H Lyman-$α$ lines provide potential probes of atmosphere-interior exchange. These findings link atomic-scale interactions to planetary-scale observables, providing new constraints on the origins of Earth-to-Neptune-sized worlds.
title The Fate of Hydrogen and Helium: From Planetary Embryos to Earth- and Neptune-like Worlds
topic Earth and Planetary Astrophysics
Materials Science
Atmospheric and Oceanic Physics
Computational Physics
url https://arxiv.org/abs/2510.24956