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MCQIntermediateStars & Stellar Evolution
USAAAO — 2023 First Round
Question 11
Consider a main-sequence star with mass M = 9.1 × 10^29 kg, which is sustained through the proton-proton chain reaction, which operates with ϵ = 0.7% efficiency. The hydrogen and helium fractions of this star are fH = 0.71 and fHe = 0.22 at the beginning of its lifetime. Assume this star has solar luminosity and that all hydrogen can be used for fusion. Calculate the lifetime of this star.
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Source
USAAAO 2023 First Round. Question text, choices, and answer were transcribed from the official USAAAO exam and solutions PDFs.