When is a star considered a white dwarf?

Question

HIX Tutor · Accepted Answer

undefined A star is considered a white dwarf when it has burned up most of its fuel and is no longer able to sustain nuclear reactions in its core. This happens after a star like our Sun runs out of hydrogen fuel and expands into a red giant. Then, it sheds its outer layers and becomes a white dwarf. So, to sum it up, a star becomes a white dwarf after it goes through the red giant phase and sheds its outer layers.

Hailey Alexander · Answer

When hydrogen burning is almost over the star first become red giant.

The majority of stars experience this under the Chandra-Sekhar limit, wherein no fusion occurs and the star is supported by electron degeneracy pressure. The outer layers puff out to form a planetary nebula, and the inner mass shrinks and stops with a pressure known as degenerative pressure.

Ian Aitchison · Answer

undefined When a star runs out of nuclear fuel and collapses due to its own gravity, it becomes a white dwarf. It becomes extremely hot and dense, but it is no longer experiencing nuclear fusion reactions in its core.