According to present understanding, a nova is caused by .
A)a white dwarf that gains enough mass to exceed the 1.4- solar- mass limit
B)hydrogen fusion on the surface of a neutron star
C)hydrogen fusion on the surface of a white dwarf
D)carbon fusion in the core of a white dwarf

Question

Quizplus · Accepted Answer

A nova occurs when a white dwarf in a binary system accretes matter from its companion star, causing hydrogen fusion to occur on the surface of the white dwarf. This leads to a runaway fusion reaction, resulting in a sudden increase in brightness. It is distinct from a supernova, which involves a catastrophic explosion of a star. Option A refers to a different phenomenon called a Type Ia supernova. Option B is incorrect as neutron stars do not have a surface for hydrogen fusion to occur. Option D refers to a hypothetical event called a carbon detonation, which has not been observed in nature.

According to Present Understanding, a Nova Is Caused by