The Death

of the SunMichael Liu

Institute for Astronomy

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Core of the Sun

Temperature of ~15 million Kelvin

Every second,600 million tons of hydrogen are fused into 596 million tons of helium.

The Sun

today

The Sun in5 billion years: 2000x more heat

100x larger

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5 billion yearsfrom today

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Today

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6 billion yearsfrom today

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The Sun is in gravitational equilibrium

• The outward push of pressure balances the inward pull of gravity.

• The energy provided by fusion in the core provides the outward pressure.

• The inward pull of gravity (the weight of the outer layers) causes the core to very hot and dense.

Stage #2: Red giant phaseH-burning shell with inert He core

Main sequence star(core H burning)

Red giant star(H-shell burning)