Which is the most common type of temporary star?

The most common type of temporary star is a nova. A nova occurs when a white dwarf star, which is the remnant of a small to medium-sized star that has exhausted its nuclear fuel, undergoes a sudden increase in brightness. This happens when hydrogen from a companion star accumulates on the surface of the white dwarf and is ignited in a thermonuclear explosion. This process can cause the brightness of the star to increase dramatically, often by a factor of thousands, for a short period, typically lasting from a few weeks to a few months before it fades back to its original state.

In contrast, a supernova represents a much more energetic and rare event leading to the explosive death of a star, typically occurring only at the end stages of a massive star's life cycle or as a result of a binary star system's dynamics. Exoplanets are not stars, but rather planets that orbit other stars outside our solar system. A neutron star is the collapsed core of a massive star that has undergone a supernova, and while it is a fascinating object in astrophysics, it is not a type of temporary star in the same sense as a nova. Thus, considering the transient nature and frequency of brightness changes, novae are indeed the most