From acc4b928f2e4a28a96eb57ab208e8961effaddee Mon Sep 17 00:00:00 2001 From: Senrokai Date: Tue, 29 Sep 2026 21:50:29 +0200 Subject: [PATCH] Say that Makemake's day is known only to a factor of two, citing both readings f655a4c kept Makemake's SBDB period, 22.83 hours, saying "nothing later overturns it", a reading its author had not checked. The SBDB flags that period as Eris's was ("may be wrong by 30 percent or so"). Hromakina et al. 2019 give 22.8266 h as the double-peaked period a "possible lightcurve asymmetry suggests", of a light curve that repeats every 11.4 h. Kiss et al. 2024 (arXiv:2410.22544), with TESS and Gaia, find the 11.401 +/- 0.076 h single peak again, "cannot confirm that the double-peaked 22.8 h is Makemake's true rotation period", and take 11.4 h as their default. Nothing is changed in what is drawn: the literature does not settle which it is, and 22.83 stays as the SBDB's. The Makemake spec now cites both papers and says the drawn day may be twice the real one, and the renderer's comment no longer calls the three dwarf planets' periods known. Co-Authored-By: Claude Opus 5.5 (1M context) --- src/app/features/galaxy-system/system-orbits-renderer.ts | 3 ++- tools/etl/fetchSolarSystem.ts | 6 ++++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/src/app/features/galaxy-system/system-orbits-renderer.ts b/src/app/features/galaxy-system/system-orbits-renderer.ts index b721fca..54186ac 100644 --- a/src/app/features/galaxy-system/system-orbits-renderer.ts +++ b/src/app/features/galaxy-system/system-orbits-renderer.ts @@ -258,7 +258,8 @@ const HOURS_PER_DAY = 24; /** * How a body the IAU gives no rotational elements for is turned at a given date — Eris, Haumea - * and Makemake, whose periods are known and whose poles are not: at its own sidereal rate, about + * and Makemake, whose periods are measured (Makemake's only to a factor of two, see its spec in + * `fetchSolarSystem.ts`) and whose poles are not: at its own sidereal rate, about * its orbit's normal, backwards for a negative period. None of them has an obliquity, so none is * applied. The phase is arbitrary: each body starts at its elements' epoch in the shortest * rotation of +Y onto its axis, and turns from there. Exoplanets have no published rotation at diff --git a/tools/etl/fetchSolarSystem.ts b/tools/etl/fetchSolarSystem.ts index 259dc2d..aceec1e 100644 --- a/tools/etl/fetchSolarSystem.ts +++ b/tools/etl/fetchSolarSystem.ts @@ -106,6 +106,12 @@ const BODY_SPECS: BodySpec[] = [ // SBDB itself flags as "may be wrong by 30 percent or so": it turns once in 15.771 +/- 0.008 days // (Bernstein et al. 2023, PSJ 4, 115), locked to Dysnomia's 15.786-day orbit (Szakáts et al. // 2023, A&A 669, L3). On the SBDB's figure it turned 14.6 times too fast. + // + // Makemake's day, the SBDB's 22.83 hours, carries the same flag and is not settled either: it is + // the double-peaked reading Hromakina et al. 2019 (A&A 625, A46) give as "possible" of a light + // curve that repeats every 11.4 hours. Kiss et al. 2024 (ApJL, arXiv:2410.22544) find that 11.40 + // +/- 0.08 hour single peak again with TESS and Gaia, cannot confirm the 22.8, and take 11.4 as + // their default. Neither overturns the other; the SBDB's 22.83 is kept, and may be twice the day. { id: 'eris', name: 'Eris', kind: 'dwarf', horizonsCommand: '136199;', center: '500@10', sbdb: 'Eris', radiusKm: 1163, rotationPeriodHours: 15.771 * 24 }, { id: 'haumea', name: 'Haumea', kind: 'dwarf', horizonsCommand: '136108;', center: '500@10', sbdb: 'Haumea', radiusKm: 797.6 }, { id: 'makemake', name: 'Makemake', kind: 'dwarf', horizonsCommand: '136472;', center: '500@10', sbdb: 'Makemake', radiusKm: 715 },