what did Jupiter lack that kept it from?

Question

firing up into another sun?.... mass?... or something else?....and, considering it's place in the solar system, COULD it have been a second sun, orbiting Old Sol?....

if it had ignited... would it have had disasterous effects on Earth?....or is it far enuff away that we'd not have been terribly affected?....

Answer 1

Please search a similar question using the words
[jupiter] [star] [failed]
From there I'd copy this:
►►The Sun is a small star, but has 1000 times the Jupiter mass. To be a brown dwarf star, Jupiter would need 100 times its mass.
1► When the Solar System was young, the hydrogen and other elements were available to grow. Now the space is almost empty.
2►Actually Jupiter radiates more energy than the one received from the Sun, so it is possible that some (but very little) fusion occurs. Jupiter could be considered as a quasi-star, but this condition is forever.
3► The stars come from gas clouds. If the cloud were larger, the star would be larger, or more stars would be born (multiple systems)
4►As the gas cloud collapses, the temperature increases, due to the pressure and to the fusion. The equilibrium stabilizes the size, the temperature, the fusion rate, and the pressure. After some billion years, the star don't have the hydrogen required for the equilibrium, and a new equilibrium must start with the helium as a fuel

Answer 2

Mass.
For Jupiter to become even the smallest star that fuses hydrogen, it would need to be 75 more massive than it currently is.
Since about 90% of the mass in the protoplanetary disk ends up in the central star, there isn't a lot of mass left for a planet to collect and become a star. When the central star ignites, the solar wind it creates can sweep a lot of the gas and dust out of the forming solar system.

Answer 3

Mass. Last I knew there were some who suspected that there are low level hydrogen fusion reactions going on inside Jupiter. Not enough to make is shine in visible light, but in infa-red. I think this idea might be outdated, though, because I'm also hearing that they think Jupiter has a solid core again.

Anyway, if Jupiter were quite a bit more massive it would certainly be a star. As it is, it may be a sub-star

Answer 4

Just mass.

It could have been a second sun if it had acquired enough gas to produce internal temperatures hot enough to burn hydrogen.

There are in fact lots of binary star systems in the universe.

Answer 5

Jupiter would have to be about 80+ times as massive as it is now in order to become a star.

Answer 6

Mass is probably the best conclusion.

Answer 7

Because God didn't allow it to do so.