What is Sirius B classified as?

Sirius B is classified as a white dwarf, which is a final evolutionary stage for stars that were once similar to our Sun in terms of mass. This classification is based on its properties; white dwarfs are typically small, dense remnants of stars that have exhausted their nuclear fuel. After a star like Sirius A (its companion) has burned through its hydrogen and later helium, it sheds its outer layers, leaving at its core the hot, blue-white remnant we observe as a white dwarf.

The characteristics of white dwarfs include high temperature and low luminosity, as they primarily emit light from residual heat rather than ongoing nuclear fusion processes. Sirius B, in particular, was one of the first white dwarfs to be identified, and it plays a significant role in our understanding of stellar evolution. It emits a significant amount of ultraviolet radiation, which is typical for white dwarfs, contributing to its classification in this category.