Which critical mass threshold must a white dwarf exceed to trigger a Type Ia supernova?

Answer

The Chandrasekhar limit.

When a white dwarf in a binary system accretes enough mass to pass the Chandrasekhar limit, it triggers runaway thermonuclear fusion leading to a complete disintegration.

Which critical mass threshold must a white dwarf exceed to trigger a Type Ia supernova?
astronomyuniversebrightnesssupernovas