Stellar Classes
Class O
- Examples
- Mintaka (Delta Orionis)
- Color
- Dark Blue
- Temperature
- 28,000 to 50,000 Kelvin
- Composition
- Ionized atoms, especially helium
Class B
- Examples
- Rigel, Spica
- Color
- Blue
- Temperature
- 10,000 to 28,000 Kelvin
- Composition
- Neutral Helium, some hydrogen
Class A
- Examples
- Sirus A
- Color
- Light Blue
- Temperature
- 7,500 to 10,000 Kelvin
- Composition
- Strong hydrogen, some ionized metals
Class F
- Examples
- Procyon A
- Color
- White
- Temperature
- 6,000 to 7,000 Kelvin
- Composition
- Hydrogen and ionized metals, calcium and iron
Class G
- Examples
- Sol
- Color
- Yellow
- Temperature
- 5,000 to 6,000 Kelvin
- Composition
- Ionized Calcium, both neutral and ionized metals
Class K
- Examples
- Alpha Centauri B, Arcturus
- Color
- Orange
- Temperature
- 3,500 to 5,000 Kelvin
- Composition
- Neutral metals
Class M
- Examples
- Wolf 359, Betelgeuse
- Color
- Red
- Temperature
- 2,500 to 3,500 Kelvin
- Composition
- Ionized atoms, especially helium
Stellar Class Subdivisions
Each star class is divided into 10 subclasses, ranging from 0 (hottest) to 9 (coolest). Stars are also divided into six categories according to luminosity:
- Ia (most luminous supergiants)
- Ib (less luminous supergiants)
- II (luminous giants)
- III (normal giants)
- IV (subgiants)
- V (main sequence and dwarfs)
- VI (subdwarfs)
- VII (white dwarfs)
Example: Earth’s star, Sol would be rated as a G2V, which means that it is a relatively hot (2) G-Class (G) main sequence star (V). So when naming the sub-class of a star they should be named in the following format:
[Letter of class][Temperature number 0 to 9][Luminosity category]
Note
Classes R, N, S, T, Q, and W are not in the main sequence above. They are used for rare star types. More information on these classes will be listed if/when it becomes available in later Paramount-approved products or episodes