{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"b70b27f879e63202bcd97eb7952dc9eb93acb735e97002e2e46b78f46e368044","created":"2026-10-03T07:17:55Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","fb7f3de0a8fab5711f05e03646a12394509c61354388184d4f33810f4e2b2f0d"],"salt":"708ccec38071b13de932f0948fce58c78891a3bb9ccf5b9df9cc55e328adfd90","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"astro.radius-valley.age-dependence","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"fb7f3de0a8fab5711f05e03646a12394509c61354388184d4f33810f4e2b2f0d","relation":"special_case"}],"plain":"Photoevaporation should finish stripping planets within about 100 million years, while core-powered loss takes about a billion. Comparing young and old planet populations can separate them.","posed_since":"","precise":"Measure the ratio of sub-Neptunes to super-Earths and the gap location in clusters, associations and field stars with ages $10^7-10^10\\ \\mathrm{yr}$. Photoevaporation predicts the ratio settles by $\\sim 10^8\\ \\mathrm{yr}$; core-powered mass loss predicts evolution until $\\sim 1-2x10^9\\ \\mathrm{yr}$. The answer is the measured time dependence with enough planets per age bin to distinguish the two.","problem_ref":null,"references":"","settled_by":"Ages from cluster membership, gyrochronology or asteroseismology for several hundred small planets with precise radii.","status_note":"Analyses of 2020-2023 (Berger et al. 2020; David et al. 2021; Christiansen et al. 2023) report the small-planet population changing over Gyr timescales, which favors core-powered mass loss; samples of planets younger than $10^{8}\\,\\mathrm{yr}$ remain small.","title":"Does the radius valley form in 100 Myr or over billions of years?","topic_ref":"29eecacca9d688759063e837d47b7481ed1a91ff74dcb512159e65510cf6039a"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5f8510627af114dc249446080eca8205eb27794db2b05bfeb2e1d04cf02d5546","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"4029ab07356bc749666562e6983e9ec639eed7f40839e51245fd2eb7d607ee44","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"L_pb44pEzpvFzdC8IZvKeneNtBE8mmXLAmWZ3AXndCqxIJef0NRzRjj-YYCYtlrFlKnx4Y4-PBo_rzNDk1wIDw"},"schema":"pubphys.envelope/1"},"record_hash":"5f8510627af114dc249446080eca8205eb27794db2b05bfeb2e1d04cf02d5546","leaf_index":597}