O star
[oh stahr]
noun
a very hot, massive, blue star of spectral type O, having a surface temperature between 30,000 and 50,000 K and an absorption spectrum with few lines, though the Balmer series of hydrogen lines is present and lines of ionized helium are detectable.
Compare spectral type.
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Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019