A star - A stars lifetime on the main sequence is...

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A star’s lifetime on the main sequence is proportional to its mass divided by its Luminosity * The duration of a star’s main sequence lifetime depends on the amount of hydrogen in the star’s core and the rate at which the hydrogen is consumed * The more massive a star, the shorter is its main-sequence lifetime * The Sun has been a main-sequence star for about 4.56 billion years and should remain one for about another 7 billion years 1. During main sequence part of a light weight stars life, the H in the core is fused into He. a. Core is 10% of inner area. b. Phase continues for about 10 billion years. c. During a star’s main-sequence lifetime, the star expands somewhat and undergoes a modest increase in luminosity 2. After 10 years no H is left in the core. a. Core is entirely He. b. H still undergoing fusion in shell around the core. c. ½ way through lifetime. 3. During the time there is no fusion at the core: a. Thermal pressure decreases. b.
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A star - A stars lifetime on the main sequence is...

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