Stellar classification (astrophysics)

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Stars are classed by various properties. A common classification is surface temperature. Beginning with early spectral schema in the 19th century ranking stars from A to P, the spectral classification, called “Morgan-Keenan spectral classification” [1] now ranks stars in seven main types: A, B, A, F, G, K, M.[2] Each spectral classification is further divided into tenths. Our sun, Sol is a G2.

Classification system

The stars are ranked from hottest to coldest: Class Temperature Star colour

  • O 30,000-60,000 °K Blue
  • B 10,000-30,000 °K Blue
  • A 7,500-10,000 °K White
  • F 6,000-7,500 °K White (yellowish)
  • G 5,000-6,000 °K Yellow (e.g. Earth’s sun)
  • K 3,500-5,000 °K Orange
  • M 2,000-3,5000 °K Red

[3]

References

  1. Note: based on the work of Annie Cannon and other astronomers from the Harvard College Observatory
  2. A popular mnemonic for this is Oh Be A Fine Girl, Kiss Me
  3. Star classification

External Links