{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"801954c4363a71f9ade90480498c796c67c41a20831d6c0bcf0c431bbf93f045","created":"2026-10-03T07:17:55Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","c1da01cccdab995103bb69427c0d76cbe17fda1b6a2e1c2046fa8d24c99ef764"],"salt":"0371e038024691cad900185602d6f02d8877f45c1f9829be6985d386be3e456e","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"astro.radius-valley.magma-envelope-coupling","kind":"phenomenon","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"c1da01cccdab995103bb69427c0d76cbe17fda1b6a2e1c2046fa8d24c99ef764","relation":"special_case"}],"plain":"Under a thick hydrogen layer, the rocky surface of a sub-Neptune may be molten, and hydrogen can dissolve into it and react with the rock to make water and other gases. This would change what the planet's atmosphere looks like from outside.","posed_since":"","precise":"For sub-Neptunes with surface magma oceans at T ~ 2000-4000 K under H2 envelopes of ~ 1-3 percent of the planet mass, determine how H2 dissolution into silicate melt and reactions with the melt (FeO and SiO2 reduction producing H2O, SiO and SiH4) set the envelope composition and its mean molecular weight $\\mu$. The answer is predicted $\\mu$ and H2O, CO2 and SiO abundances versus equilibrium temperature and envelope mass fraction, testable against JWST spectra.","problem_ref":null,"references":"","settled_by":"Coupled magma-atmosphere equilibrium and evolution models that predict the dependence of $\\mu$ on equilibrium temperature, confirmed by JWST spectra of a sample of sub-Neptunes spanning that temperature range.","status_note":"","title":"How do magma oceans change sub-Neptune atmospheres?","topic_ref":"29eecacca9d688759063e837d47b7481ed1a91ff74dcb512159e65510cf6039a"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"061d3f762ee73dd15d6422c8431eba2713dde74fb8a7936ae76cd7493a1c29c7","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"eae5c98ac8ad2e94952883b16b73279feff59c1d28834b055fd11bc0fc44c6b7","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"82EjJpwqeBs-eWZNGK_pBsRQ2BkwfCeKCzJzsSOzTjCPnagry5h77_bOuuFdsu_7NQvmIMmpPMfwAEOwzs9nDw"},"schema":"pubphys.envelope/1"},"record_hash":"061d3f762ee73dd15d6422c8431eba2713dde74fb8a7936ae76cd7493a1c29c7","leaf_index":600}