Here's why:

* Small: White dwarfs are the remnants of stars like our Sun after they have exhausted their nuclear fuel. They have shed their outer layers, leaving behind a dense, Earth-sized core.

* Hot: While they are small, white dwarfs are incredibly hot. They have surface temperatures ranging from 25,000 to 100,000 Kelvin, much hotter than our Sun.

Note:

While white dwarfs are small and hot, they are not stars in the traditional sense. They don't generate energy through nuclear fusion like stars do. Instead, they are slowly cooling down over billions of years.