What would you be most likely to find if you returned to the solar system in 10 billion years?

a white dwarf

Explanation:

A white dwarf, is otherwise known as a degenerate dwarf, it is a stellar core remnant which is mostly composed of electron-degenerate matter. A white dwarf is very dense, and has a mass which is comparable to that of the Sun, while its volume is comparable to that of Earth. It faint luminosity comes from the emission of stored heat energy; and no fusion takes place in a white dwarf