Hertzsprung- Russell diagram

Sketch and recognise the main components of the Hertzsprung- Russell diagram (HR diagram).

Hertzsprung and Russell were two astronomers who, independently of each other, produced a diagram that shows the relationship between a star's temperature and luminosity.

The diagram has a prominent diagonal band called the 'main sequence' Here there are stars such as our own with a range of temperatures and luminosity.

Cooler but brighter stars appear as giants toward the top right, while hotter but dimmer stars appear as dwarfs in the bottom left.

We can plot the pattern of a star's evolution on this diagram.

A star like our own will swell to become a giant and then dim to become a white dwarf.


Animation New Window

HR animation HR Diagram

Image New Window

Links New Window

Aspire.cosmic-ray.org Interactive HR diagram

Exam Tip

Try to remember these main components of the diagram:

  • Magnitude
  • Spectral Class (OBAFGME)
  • Position of Sun (G - Main sequence)
  • Shape of main sequence
  • Position of giants & super giants
  • Position of white dwarfs