What minimum mass is required for a star to sustain fusion all the way to iron?

Only the most massive stars, beginning their lives at perhaps eight times the Sun's mass or greater, can compress their cores sufficiently.

The path to creating an iron core requires increasingly higher core temperatures and pressures to initiate successive fusion stages (carbon to neon, neon to oxygen, etc.). Only stars possessing immense initial gravitational power can generate and sustain these extreme conditions long enough for fusion to proceed all the way to iron. Stars with lower initial masses, such as those similar to our Sun, lack this gravitational strength; their internal pressure is only sufficient to fuse elements up to carbon or oxygen before they contract, cool, and end their lives gently as white dwarfs, never reaching the necessary conditions for iron production.