Star

:This article is about celestial bodies. {{otheruses}}

Star classification

There are different classifications of stars ranging from type W which are very large and bright, to M which is often just large enough to start ignition of the hydrogen. Some of the more common classifications are O, B, A, F, G, K, M, and can perhaps be more easily remembered using the mnemonic "Oh, Be A Fine Girl, Kiss Me" (variant: change "girl" to "guy"), invented by Annie Jump Cannon (1863-1941). There are many other mnemonics for star classification; the most frequent addition tacks Right Now Sweetheart for the red dwarf sub-types R, N and S.

Related Topics:
Classifications of stars - Mnemonic - Annie Jump Cannon - 1863 - 1941 - Other mnemonics

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Each letter has 9 subclassifications. Our Sun is a G2, which is very near the middle in terms of quantities observed. Most stars fall into the main sequence which is a description of stars based on their absolute magnitude and spectral type. The Sun is taken as the prototypical star (not because it is special in any way, but because it is the closest and most studied star we have), and most characteristics of other stars are usually given in solar units.

Related Topics:
Main sequence - Absolute magnitude - Spectral type - Sun

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For example, the mass of the Sun is

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:MSun = 1.9891×1030 kg

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The masses of other stars can be given in terms of MSun.

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