Read a star's bolometric correction off its colour, and carry Gaia's G to V first

A star's luminosity was its absolute magnitude plus a bolometric correction read off its spectral
type, with its magnitude taken as V whatever band it was in. Gaia classifies none of its stars, so
all of its 379 000 got the Sun's correction, and their G was read as V: TRAPPIST-1 came out at a
seventh of its luminosity.

The dwarf sequence spectral.ts already reads types off (Pecaut & Mamajek 2013, table 5, online
version 2022.04.16) now carries its effective temperature, bolometric correction to V and Gaia
G-V columns, and dwarfSequenceAtColor interpolates them at a colour, in the colour's own system.
luminositySolar uses it wherever the star's colour is inside the table: the G magnitude is
carried to V, then corrected. Only without such a colour does it fall back to the spectral type,
as before.

Against the archive's own st_lum for the 1 449 hosts that are catalogue stars, the median error
goes from 0.038 to 0.022 dex and the 90th percentile from 0.292 to 0.115 dex; within a factor of
1.5, 84.5 % -> 93.8 %. For the 572 hosts Gaia describes: 90th percentile 0.332 -> 0.073 dex,
81.8 % -> 97.0 % within a factor of 1.5. Barnard's Star with no type now reads 0.0029 L_sun
against 0.0035 published, and TRAPPIST-1 7.3e-4 against 5.5e-4 (Agol et al. 2021).

Across the catalogue, 311 255 of 455 608 stars move by more than 10 % (median ratio 0.90: a
G-type star's G is 0.16 brighter than its V), and so do the hosts of 3 158 planets, whose
equilibrium temperatures follow as the fourth root.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/app/features/body-detail/body-view-model.ts

@@ -16,7 +16,8 @@ export interface BodyCatalogues {
 
 /**
  * Bolometric luminosity of a star in solar units, from what the catalogue measured: apparent
- * magnitude, parallax distance, and a bolometric correction read off the spectral type.
+ * magnitude in its band, parallax distance, and a bolometric correction read off the colour, or
+ * off the spectral type where there is no colour.
  */
 export function luminosityOf(star: StarRecord | undefined): number | null {
   if (!star) {
@@ -26,6 +27,9 @@ export function luminosityOf(star: StarRecord | undefined): number | null {
     magnitude: star.magnitude,
     distancePc: Math.hypot(star.x, star.y, star.z),
     spectralType: star.spectralType,
+    magnitudeBand: star.magnitudeBand,
+    colorIndex: star.colorIndex,
+    colorSystem: star.colorSystem,
   });
 }