B-type star

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B-type star

astronomy

Also known as: B star

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June 18, 2026

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A B-type star is a bluish-white star characterized by a surface temperature of around 20,000 kelvins. These stars are part of the spectral classification system, ordered by temperature from hottest to coolest: O, B, A, F, G, K, M. B-type stars are hotter than A-type stars and cooler than O-type stars. Their spectra prominently feature lines of neutral helium and singly ionized oxygen, nitrogen, and neon. In the Hertzsprung-Russell diagram, B-type stars are found among the hottest and brightest on the main sequence. Rigel is an example of a B-type star.12345

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diffuse ionized gas
…luminosity of all O and B stars. This energy output is about equal to the total power provided by supernovae, but the latter radiate most of their energy either in nonionizing radiation or in providing kinetic energies to their expanding shells. Other potential energy sources fall far short.
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…luminosity of all O and B stars. This energy output is about equal to the total power provided by supernovae, but the latter radiate most of their energy either in nonionizing radiation or in providing kinetic energies to their expanding shells. Other potential energy sources fall far short.
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Populations I and II
…very hot blue-white O and B types (some of which are less than one million years old), are designated as extreme Population I objects. All known Population I members occur near and in the arms of the Milky Way system and other spiral galaxies. They also have been detected in…
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…very hot blue-white O and B types (some of which are less than one million years old), are designated as extreme Population I objects. All known Population I members occur near and in the arms of the Milky Way system and other spiral galaxies. They also have been detected in…
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star
Classification of spectral types
The hot B-type stars, such as Epsilon Orionis, are characterized by lines of helium and of singly ionized oxygen, nitrogen, and neon. In very hot O-type stars, lines of ionized helium appear. Other prominent features include lines of doubly ionized nitrogen, oxygen, and carbon and of triply…
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The hot B-type stars, such as Epsilon Orionis, are characterized by lines of helium and of singly ionized oxygen, nitrogen, and neon. In very hot O-type stars, lines of ionized helium appear. Other prominent features include lines of doubly ionized nitrogen, oxygen, and carbon and of triply…
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Milky Way Galaxy
Stellar associations
…of spectral types O and B. They have absolute luminosities as bright as any star in the Galaxy—on the order of one million times the luminosity of the Sun. Such stars have very short lifetimes, only lasting a few million years. With luminous stars of this type there need not…
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…of spectral types O and B. They have absolute luminosities as bright as any star in the Galaxy—on the order of one million times the luminosity of the Sun. Such stars have very short lifetimes, only lasting a few million years. With luminous stars of this type there need not…
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stellar classification
Class B stars typically range from 10,000 K to 25,000 K and are also bluish white but show neutral helium lines. The surface temperatures of A-type stars range from 7,400 K to about 10,000 K; lines of hydrogen are prominent, and these stars are white.…
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Class B stars typically range from 10,000 K to 25,000 K and are also bluish white but show neutral helium lines. The surface temperatures of A-type stars range from 7,400 K to about 10,000 K; lines of hydrogen are prominent, and these stars are white.…
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