Appendix twelve

Spectral Type


spectral type surface temperature (°C) examples

O 40000 - 25000
Zeta Puppis (supergiant)
B 25000 - 11000

Spica (main sequence)

Regulus (main sequence)

Rigel (supergiant)

A 1100 - 7500
Vega (main sequence)
Sirius (main sequence)
Deneb (supergiant)
F 7500 - 6000
Canopus (supergiant)
Procyon (subgiant)
Polaris (supergiant)
G 6000 - 5000
Sun (main sequence)
Alpha Centauri (main sequence)
Tau Ceti (main sequence)
Capella (giant)
K 5000 - 3500
Epsilon Eridani (main sequence)
Arcturus (giant)
Aldebaran (giant)
M 3500 - 3000
Barnard's star (main sequence)
Antares (supergiant)
Betelgeuse (supergiant)

Spectral type: a way of classifying stars into groups according to the nature of their spectrum. The spectral type is a rough guide to the temperature of the star. In order from hottest to coolest, the spectral types are lettered as follows: O, B, A, F, G, K, M. Each spectral type is also subdivided into ten sub-groups from 0 to 9.

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