- Demonstrate an understanding of how stars can be classified according to their spectral type
- Demonstrate an understanding that a star's colour is related to its temperature


Each of these types is divided into further categories of 0 to 9. The Sun is classed as a G2 star.

There are further categories of W (Hotter than O) and R, N & S (cooler than M). These are very rare stars and you don't need to know about these for the exam.


Features of different types of stars
Type Colour Temperature Spectral lines
O Violet -white 30,000° K+
Helium with Hydrogen
B Blue-white 12,000 -
30,000° K
Hydrogen with Helium
A White 8,000 -
12,000° K
Hydrogen Rich
F Yellow-White 6,000 -
8,000° K
G Yellow 5,000 -
6,000° K
Some Iron lines
K Orange 3,000 -
5,000 ° K
Many Metallic lines
M Red <3,000 ° K

Metallic and Carbon lines



Give an example of how a star's colour is related to its temperature

Drag & Drop

Remember the types of stars from hottest to cooles using a helpful mnemonic:
e.g. Oh Be A Fine Girl Kiss Me
Er... some are better than others. Check out the link to other mnemonics below.