Describe the key features of stellar spectra and describe how these are used to classify stars
- Stars are divided into seven spectral classes based on their surface temperatures: O, B, A, F, G, K and M (Oh Be A Fine Girl Kiss Me).
- O is the hottest class.
- M is the coolest class.
- Each class is divided into ten further subdivisions using the numbers from 0 to 9.
- Our sun is a G2 star.
- The hotter a star is, the shorter its dominant wavelength is.
- Thus, by observing wavelengths through spectroscopy, temperature can be determined and stars can be classified.