What imbalance immediately triggers the catastrophic implosion known as gravitational collapse in a dying star?

Answer

The cessation of outward thermal and radiation pressure that counteracted gravity

Gravitational collapse begins when the star exhausts its nuclear fuel, causing the outward pressure generated by fusion to cease, thereby allowing the relentless inward tug of gravity to dominate.

What imbalance immediately triggers the catastrophic implosion known as gravitational collapse in a dying star?
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