Suppose a white dwarf is gaining mass because of accretion from a binary companion. What happens if its mass reaches the 1.4 solar mass limit?
A) The white dwarf undergoes a collapse and expels the excess mass in a nova eruption.
B) The white dwarf (which is made mostly of carbon) suddenly detonates carbon fusion and this creates a white dwarf supernova explosion.
C) The white dwarf immediately collapses into a black hole, disappearing from view.
D) A white dwarf can never gain enough mass to reach the limit because a strong stellar wind prevents the accreting material from reaching it in the first place.

Question

Quizplus · Accepted Answer

When a white dwarf gains mass and reaches the 1.4 solar mass limit, it can no longer support its own weight with electron degeneracy pressure. At this point, the core of the white dwarf becomes hot and dense enough for carbon fusion to occur explosively, which rapidly releases a huge amount of energy and generates a Type Ia supernova. The explosion completely destroys the white dwarf, leaving no remnant behind. This process is believed to be responsible for producing most of the iron in the universe and is used as a standard candle for measuring distances in the cosmos.

Suppose a White Dwarf Is Gaining Mass Because of Accretion