Spectral type
The term spectral type in astronomy referred to the stellar magnitude of a star based on its temperature and color. Among the spectral types were the O-type star, F-type star, and G-type star.

The sun in the Sigma Draconis system was classified with a spectral type of Gamma 9. ()

Appendices

Background information 
The traditional scientific classification scheme, called the Harvard system, from hottest to coolest stars is:

 O-type star (blue in color) – Mintaka A, Idran B and C
 B-type star (blue white to deep blue white) – Rigel
 A-type star (white to blue white) – Idran A, Vega, Sirius A
 F-type star (yellow white to white) – Orellius Minor, Canopus, Procyon A
 G-type star (yellow to yellowish white) – Calindra, Hemikek, Sol
 K-type star (orange) –  Alpha Centauri B, Aldebaran, 40 Eridani A
 M-type star (orange red) – Proxima Centauri, Betelgeuse, 40 Eridani C

It is unknown to which of those spectral types a "Gamma 9" could belong to; it is possibly a subtype of the G-type star, like a G1 star.

External links

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Astronomical classifications