What mass threshold must a collapsing core exceed to become hot and dense enough to initiate sustained hydrogen fusion and become a true star?

Answer

0.08 times the mass of the Sun (or 80 times Jupiter's mass)

If the core fails to accumulate about 0.08 solar masses (or 80 Jovian masses), it cannot reach the necessary temperature for sustained hydrogen fusion.

What mass threshold must a collapsing core exceed to become hot and dense enough to initiate sustained hydrogen fusion and become a true star?
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