Kelvin-Helmholtz timescale

Kelvin–Helmholtz timescale

The time taken for a mass of gas to collapse under its own gravitation. It is given by τ_KH = GM ²/RL where G is the gravitational constant and M, R, and L are the mass, radius, and luminosity of the object. It is thought to describe the evolutionary timescale of a pre-main-sequence star. Such a collapse – known as the Kelvin–Helmholtz contraction – was proposed in the late 19th century as the source of the Sun's energy output. This theory was abandoned when the contraction timescale of only 10⁷ years was shown to be too short. The energy source was subsequently shown to originate in nuclear-fusion reactions.

单词	kelvin-helmholtz timescale
释义	Kelvin-Helmholtz timescale Kelvin–Helmholtz timescale The time taken for a mass of gas to collapse under its own gravitation. It is given by τ_KH = GM ²/RL where G is the gravitational constant and M, R, and L are the mass, radius, and luminosity of the object. It is thought to describe the evolutionary timescale of a pre-main-sequence star. Such a collapse – known as the Kelvin–Helmholtz contraction – was proposed in the late 19th century as the source of the Sun's energy output. This theory was abandoned when the contraction timescale of only 10⁷ years was shown to be too short. The energy source was subsequently shown to originate in nuclear-fusion reactions.
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