If Jupiter became a star..?

[KennyR]

Jupiter doesn't have a hundredth of the mass of even the smallest star. Ain't ever gonna happen.

[KennyR]

whabang wrote:
Jupiter doesn't have quite the mass for achieving brown-dwarf status (a star that never managed to light up), but it's not very far away.

It is. If it was forty times heavier it wouldn't be a brown dwarf 'star'.

I read a theory about the possibility to light up Jupiter with numerous hydrogen bombs deep inside it, should the Sun ever start fading, but I doubt it would be a good idea.

It wouldn't work. You need a sustained temperature of about 12 million kelvin and a pressure of millions of atmospheres to get a sustained fusion reaction. You might get that from a nuke - for about a split second. That's enough for some nuclear fusion, but it would stop as soon as the generated heat escaped, and that would be fast. No-one actually says there isn't fusion happening in Jupiter right now (possibly a few atoms a second) but its sustaining it that makes a star a star.

[KennyR]

speel wrote:
The sun won't fade (in theory that is)
When the sun dies, the core becomes weak, the sun expands (consuming the earth with it's flames) and after that it collapses and becomes a black hole.

Nah, our sun isn't big enough to form a black hole. It has to be over the Chahandresekar (sp?) Limit, which is about 1.4 times the size. And many bigger stars go on a crash diet to drop to this limit as they die anyway. Black holes only tend to form with really big stars.

What will happen with the sun is that, in about 10-20 billion years, it will run out of hydrogen in its core and start burning helium. Core temp will fly up and the star will expand and redden, engulfing earth. Then it will shrink to a white dwarf, maybe throwing out a lot of itself into a nebula at the same time. Then it'll cool to a lump of solid diamond and float around forever.