Yes. These will eventually cool into so-called "black dwarfs" that emit very little light. https://en.wikipedia.org/wiki/Black_dwarf https://en.wikipedia.org/wi

Yes. These will eventually cool into so-called "black dwarfs" that emit very little light. https://en.wikipedia.org/wiki/Black_dwarf https://en.wikipedia.org/wiki/Black_dwarf They cool so slowly because they are so dense it's very hard for energy to escape.