system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible for a star to be cold?

If it is, is the limit absolute zero? And a follow-up, is there any limits on how HOT things can be?
gpt
Stars can be cold if they are brown dwarfs, objects much bigger than Jupiter but not big enough to ignite nuclear fusion at their core, or black dwarfs, collapsed medium-sized stars (white dwarfs) that have radiated away all their thermal energy. The universe isn't old enough to have black dwarfs though.

relephant edit: in brown dwarves you can still have deuterium fusion, but not hydrogen fusion, and it's debatable whether these are stars are not.