What is the dim star that forms from a collapsed red giant called?

Answer 1

It is called a white dwarf. It is the penultimate stage of a star the size of the Sun, which progresses with age from a yellow or orange star, to a red giant, to a white dwarf, and ultimately (after an immensely long period of time) a black dwarf. (There are no confirmed black dwarf stars because their formation may take much longer than the current age of the universe.)

Answer 2

To be precise, it is "red supergiant" stars that explode rather than "red giant" stars.

Red giants are relatively cool (surface temperature) stars.

Our Sun will eventually become red giant.

A red supergiant is similar to a red giant, but with more mass. They usually have a mass that's at least 8 times the Sun's mass.

In a normal star, gravity is balanced by the radiation pressure caused by the nuclear fusion reactions.

In red supergiants, the nuclear fusion eventually stops at the element iron.

This leads to gravity dominating and the star suddenly collapses into itself.

A rapid "recoil" expansion follows and the star explodes in what is termed a supernova.

Answer 3

A Red Giant collapses when it exhausts its fuel. It then becomes a very dense, compact star known as a white dwarf

Answer 4

A collapsed red giant forms a white dwarf star. This is the final stage in the life cycle of low to medium mass stars like the Sun.