Classis spectralis

Classificatio harvardica

Harvardica classificatione stellae dividitur in classes O—B—A—F—G—K—M—C—S. Plerumque communes sunt stellae classium O—B—A—F—G—K—M, quae appellantur stellae normales, sed stellae cassium C—S, (atque R, N, T, L) sunt stellae peculares, i.e. stellae, habntes spectum peculare.

Tabula comparandi

Classis	Temperatura	Color verus	Coror visibilis	Massa (in massis Solis)	Rdius (in radiis Solis)	Luminoitas	Lineae Hydrogenii	% e stellis seriei capitalis
O	30,000–60,000 K	Caeruleus	Caeruleus	60 M☉	15 R☉	1,400,000 L☉	debiles	~0.00003%
B	10,000–30,000 K	albus-caruleus	albus caerleus albusque	18 M☉	7 R☉	20,000 L☉	medii	0.13%
A	7,500–10,000 K	Albus	Albus	3.1 M☉	2.1 R☉	80 L☉	lucidi	0.6%
F	6,000–7,500 K	ochroleucus	albus	1.7 M☉	1.3 R☉	6 L☉	medii	3%
G	5,000–6,000 K	flavus	ochroleucus	1.1 M☉	1.1 R☉	1.2 L☉	debiles	8%
K	3,500–5,000 K	aurantinus	rutilis	0.8 M☉	0.9 R☉	0.4 L☉	admodum debiles	13%
M	2,000–3,500 K	Ruber	flammeus	0.3 M☉	0.4 R☉	0.04 L☉	admodum debiles	>78%

Classificatio Yerkes

Factor supplementaruis afficiens in characterem spectri est densitas stratorum exteriorum stellae, dependens a massa et densitate stellae, i.e. a luminocitate. Admodum dependunt a lumnocitate SrII, BaII, FeII, TiII, propterea est differentia spectrorum stellarum-gigantum et pumilionum aequalibus classsibus harvardicis.

Ha clssificatione stella habet classem luminocitatis:

• I Supergigantes
  • Ia-0 hypergigantes vel lucidissimi supergigantes
  • Ia lucidi supergigantes, e.g. Deneb (spectrum A2Ia)
  • Iab Supergigantes mediocriter lucidi
  • Ib minus lucidi gigantes, e.g. Betelgeuse (spectrum M2Ib)
• II Lucidi gigantes
  • IIa, e.g.: β Scuti (HD 173764) (spectrum G4 IIa)
  • IIab, e.g.: HR 8752 (spectrum G0Iab:)
  • IIb, e.g.: HR 6902 (spectrum G9 IIb)
• III e.g.: gigantes
  • IIIa, e.g.: ρ Persei (spectrum M4 IIIa)
  • IIIab, e.g.: δ Reticuli (spectrum M2 IIIab)
  • IIIb, e.g.: Pollux (spectrum K2 IIIb)
• IV subgigantes
  • IVa, e.g.: ε Reticuli (spectrum K1-2 IVa-III)
  • IVb, e.g.: HR 672 A (spectrum G0.5 IVb)
• V series capitalis
  • Va, e.g.: AD Leonis (spectrum M4Vae)
  • Vb, e.g.: 85 Pegasi A (spectrum G5 Vb)
• VI suppumilionesи (rare)
• VII pumilio alba (rare)

Classificatio harvardica definit Abscissam diagrammatis Herzsprung — Russel, sed Yerkes classificatio — placies stellae in id diagrammate. Supplementaria autem praestantia hujus classificationis est possibilitas definendi luminocitatem sellae (sectro cognoto), et propterea possibilitas aestimandi distantionem ad stellam.

Sol, pumilio flava, habet classem spectralem G2V.

Vide etiam

• Stella
• Spectrum
• diagramma Herzsprung — Russel