Cambridge Encyclopedia :: Cambridge Encyclopedia Vol. 48

main sequence

In astronomy, a broad band in the Hertzsprung–Russell diagram, in which most stars lie. A star spends most of its life on this main sequence, while it burns hydrogen to helium. Once the hydrogen in the core is consumed, the star evolves away from the main sequence, becoming first a red giant. The Sun is a main sequence star.

Stellar
Class
Radius Mass Luminosity Temperature
R/R☉ M/M☉ L/L☉ K
O2 16 158 2,000,000 54,000
O5 14 58 800,000 46,000
B0 5.7 16 16,000 29,000
B5 3.7 5.4 750 15,200
A0 2.3 2.6 63 9,600
A5 1.8 1.9 24 8,700
F0 1.5 1.6 9.0 7,200
F5 1.2 1.35 4.0 6,400
G0 1.05 1.08 1.45 6,000
G2 1.0 1.0 1.0 5,700
G5 0.98 0.95 0.70 5,500
K0 0.89 0.83 0.36 5,150
K5 0.75 0.62 0.18 4,450
M0 0.64 0.47 0.075 3,850
M5 0.36 0.25 0.013 3,200
M8 0.15 0.10 0.0008 2,500
M9.5 0.10 0.08 0.0001 1,900

"Oh Be A Fine Girl, Kiss Me" is a phrase used to aid memory of the sequence.

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