system
Given the following post, respond as if you're commenting on Reddit:
human
Is there a minimal size a star can be?

I understand that stars can be massive. For example, *VY Canis Majoris* would fit inside Jupiter's orbit around our sun. But, what about small stars? Is there a minimal size they can be and still begin nuclear fusion?

(I hope I'm asking this clearly!)

Thanks, science!
gpt
Yes, though it is more useful to think about a minimum mass rather than a minimum radius. "Brown dwarfs" are the intermediate between large gas giants and the smallest red dwarf stars. There is some fuzziness about where the boundaries lie, but ~80 Jupiter masses marks the point where hydrogen fusion occurs in the core.

Brown dwarfs (and some gas giants) are able to sustain lithium fusion for a bit but the available lithium runs out real quick so it isn't a long-term power source.