{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9743aa88a9732402ca1d5e756dd9ab0de4622e91dea1af37fd7ee82a09ede589","created":"2026-10-03T07:17:55Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"d8dfd7f64e28548686859545f00e1eef937470da395ae53530162ec4e8e8840e","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"astro.sn-ia-progenitors.q-branch-delay","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"Gaia found a group of heavy white dwarfs that stop cooling for billions of years, piling up in a narrow strip (the Q branch) of the color-brightness diagram. One proposed cause is that crystals rich in neon float upward and release energy, but whether this works in detail is not settled.","posed_since":"2019","precise":"About 6 percent of white dwarfs with $M \\sim 1.08 \\text{ to } 1.23\\,M_{\\mathrm{sun}}$ show an extra cooling delay of approximately 8 Gyr on the Q branch (Cheng, Cummings and Menard 2019). Determine whether 22Ne distillation (buoyant 22Ne-depleted crystals and gravitational energy release in a C/O/22Ne mixture) reproduces the delay length, the fraction of delayed stars and the mass range with a physically motivated 22Ne abundance, and identify which progenitors (single stars, mergers) have that composition.","problem_ref":null,"references":"","settled_by":"Cooling-model fits with distillation physics to the Gaia Q-branch kinematics and number counts, with a progenitor composition derived from merger or high-metallicity evolution models.","status_note":"Bedard et al. (Nature, 2024) showed distillation can halt cooling for billions of years if 22Ne is enhanced; a 2026 study found Q-branch merger remnants lack strong magnetism (Ould Rouis et al., ApJ, 2026).","title":"Does neon-22 distillation fully explain the Gaia white-dwarf Q branch delay?","topic_ref":"725883c9f1fa87da8eacd23b3ad9211426658a588d96f1c1bbacc3e7a502c79e"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"4bab833bae28b8e4df47da8a667db194787bb209ed71d74bea33c56d4184af79","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"0dbec3649ab65dc803b29c8431596c3e68742f29c7d55df389831daf4b8248bb","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"OyHa-_lYeLrqmto9RbcshkzQW-xyf8LqO6YJcMctZjOiZGi-ch8vtpf9y0tfZj3IJyhH395sjhFr1DA1qZhPDQ"},"schema":"pubphys.envelope/1"},"record_hash":"4bab833bae28b8e4df47da8a667db194787bb209ed71d74bea33c56d4184af79","leaf_index":610}