Read a giant's temperature off its type as well as its correction, so a radius has one source

d097f4b gave a giant its type's bolometric correction but left its temperature at the dwarf its
colour reads as, and the radius drawn from the two paired a correction for one star with the
temperature of another. The M giants stayed too cool (610 of them at a median 3 275 K, Antares
3 019 against Ohnaka et al.'s 3 660), and a hot giant behind dust got a 30 000 K star's correction
at the temperature of an A star: Menkib, O7.5 Iab at B−V 0.02, was drawn at 9 517 K and 95 R☉,
Alp Cam, O9.5 Ia, at 338, where 14 and 21 are published. Rigel went from 81 to 102 R☉, Alnilam
from 57 to 108.

giantSurface now reads both off the type: G to M giants off van Belle et al.'s (2021, table 8)
interferometric scale, fitted to 191 giants from G1 to M7.75 III, with the correction the dwarf
sequence has at that temperature; O to F giants off the dwarf of their type, for which the table
gains Mamajek's O3 to O9.5 rows (without colours, which do not tell O types apart); carbon and S
stars, which no row reads and which got the Sun's −0.06 at 2 420 K, off the medians of Bergeat et
al. (2001): 2 990 K over the 441 stars of their table 10 and −2.83 over the 383 with a V magnitude,
counted again from VizieR here.

On the shipped catalogue (drawn radius in R☉, before → after, published): Antares 690 → 410 at
3 730 K (680; its luminosity from V is 0.4 dex under Ohnaka's), Aldebaran 48.5 → 44.0 (44.2),
Arcturus 22.5 → 24.1 (25.4), Menkar 160 → 103, Gacrux 118 → 73, Rigel 102 → 67 (74.1), Alnilam
108 → 33, Menkib 95 → 6.9 (14, the dust still dims it), Alp Cam 338 → 31, La Superba 133 → 311
(315) and 544 → 6 977 L☉ (8 090 from Bergeat's bolometric magnitude), 19 Psc 130 → 305 (295).
The 610 M giants now sit at a median 3 644 K (p10 3 386, p90 3 816). Against their own radii
before, the O giants' fall to a median 0.08, the B giants' to 0.62, the M giants' to 0.68, and the
K giants' rise by 8 %. It is not better everywhere: Pollux goes from 8.6 to 10.1 against 8.8,
119 Tau from 700 to 326 against 587, and Mintaka and Alnitak, placed by Hipparcos at 212 and 226
pc where they are about 380, come out 8.8 and 11.8 against 13 to 20.

Tests: the giant case in stellar.spec now checks Antares's temperature against Ohnaka's, and
Aldebaran (to a tenth) and Rigel (to a fifth) against their interferometric radii; new cases give
Menkib its type's 36 100 K and a radius within 2.5 times the published one, and La Superba a
luminosity within a fifth of Bergeat's and 2 990 K; spectral.spec covers dwarfSequenceAtType. The
scene's supergiant case now expects Antares at 350-480 R☉ where it pinned 600-760. Controls:
the luminosity or the temperature ignoring giantSurface, G-M giants read as the dwarf of their
type, their correction taken off the type instead of their temperature, O giants through the
textbook colour clamped at B0, the type index off by one subclass and carbon stars unhandled each
fail the named test.

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

src/app/shared/astro/stellar.spec.ts

@@ -122,18 +122,41 @@ describe('luminositySolar', () => {
     expect(derived / 5.53e-4).toBeLessThan(1.5);
   });
 
-  it("gives a giant its type's correction, not the cooler dwarf's its colour reads as", () => {
-    // Antares, M1 Ib at B−V 1.87 and 170 pc, and Aldebaran, K5 III: 680 R☉ (Ohnaka et al. 2013)
-    // and 44.2 (Richichi & Roccatagliata 2005). As dwarfs they came out 1 516 and 86.
+  it("reads a giant's temperature and correction both off its type, not the cooler dwarf's its colour reads as", () => {
+    // Antares, M1 Ib at B−V 1.87: 3 660 K (Ohnaka et al. 2013), where its colour's dwarf is 3 019.
     const antares = { magnitude: 1.06, distancePc: 169.78, spectralType: 'M1Ib + B2.5V', magnitudeBand: 'V', colorIndex: 1.865, colorSystem: 'B-V' } as const;
+    expect(Math.abs(effectiveTemperatureK(antares)! - 3660)).toBeLessThan(100);
+    // Aldebaran, K5 III, 44.2 R☉ (Richichi & Roccatagliata 2005), to a tenth; Rigel, B8 Ia, 74.1
+    // (Baines et al. 2018), to a fifth. With a correction off the type beside the colour's
+    // temperature, Rigel came out 101.6; with K5's own correction at 3 902 K, Aldebaran 52.
     const aldebaran = { magnitude: 0.87, distancePc: 20.433, spectralType: 'K5III', magnitudeBand: 'V', colorIndex: 1.538, colorSystem: 'B-V' } as const;
-    for (const [star, published] of [[antares, 680], [aldebaran, 44.2]] as const) {
+    const rigel = { magnitude: 0.18, distancePc: 264.55, spectralType: 'B8Ia', magnitudeBand: 'V', colorIndex: -0.03, colorSystem: 'B-V' } as const;
+    for (const [star, published, tolerance] of [[aldebaran, 44.2, 1.1], [rigel, 74.1, 1.2]] as const) {
       const radius = radiusFromLuminositySolar(luminositySolar(star)!, effectiveTemperatureK(star)!);
-      expect(radius / published).toBeGreaterThan(1 / 1.2);
-      expect(radius / published).toBeLessThan(1.2);
+      expect(radius / published).toBeGreaterThan(1 / tolerance);
+      expect(radius / published).toBeLessThan(tolerance);
     }
   });
 
+  it('reads a hot giant reddened by dust at its type, not at the cool star its colour reads as', () => {
+    // Menkib, O7.5 Iab at B−V 0.02: 14 R☉ (Krtička & Kubát 2010). At its colour's 9 517 K and its
+    // type's correction it was drawn at 95; the dust it is behind still leaves it dimmer than it is.
+    const menkib = { magnitude: 3.98, distancePc: 408.881, spectralType: 'O7.5Iab:', magnitudeBand: 'V', colorIndex: 0.016, colorSystem: 'B-V' } as const;
+    expect(effectiveTemperatureK(menkib)).toBeCloseTo(36100, 6);
+    const radius = radiusFromLuminositySolar(luminositySolar(menkib)!, effectiveTemperatureK(menkib)!);
+    expect(radius / 14).toBeGreaterThan(1 / 2.5);
+    expect(radius / 14).toBeLessThan(2.5);
+  });
+
+  it("gives a carbon star the carbon stars' correction and temperature, not the Sun's correction at an M dwarf's", () => {
+    // La Superba, C7 Iab: Bergeat et al. (2001) have it at bolometric magnitude 2.43, which at the
+    // catalogue's 310 pc is 8 090 L☉. The Sun's −0.06 at 2 420 K gave 544 L☉ and 133 R☉.
+    const laSuperba = { magnitude: 5.42, distancePc: 310.342, spectralType: 'C7Iab', magnitudeBand: 'V', colorIndex: 2.994, colorSystem: 'B-V' } as const;
+    expect(luminositySolar(laSuperba)! / 8090).toBeGreaterThan(1 / 1.2);
+    expect(luminositySolar(laSuperba)! / 8090).toBeLessThan(1.2);
+    expect(effectiveTemperatureK(laSuperba)).toBe(2990);
+  });
+
   it('clamps a pathological record instead of producing an absurd luminosity', () => {
     const absurd = luminositySolar({ magnitude: -40, distancePc: 5000, spectralType: 'O5V' })!;
     expect(Number.isFinite(absurd)).toBe(true);