So, I've heard from various works of science fiction about the prospect of turning Jupiter into a star. From what I know about the physics of such a task, it would require somehow condensing Jupiter into something quite a bit smaller than it currently is, such that the pressure is sufficient to create spontaneous fusion.
So, my questions are all assuming that somehow this is possible, what would be the results? Specifically, I'm curious as to what kind of light there would be, what size would Jupiter have to shrink to manage fusion, and something about the temperature, light output, longevity, and other properties that such a body would have to have.
Specifically, I'm going to assume that it is possible to somehow force Jupiter to shrink to the minimum size required to spontaneously fuse its current atmospheric composition spontaneously, however this might be able to happen. Also, I know that fusion forces tend to exert an expansion force, let's assume that this can be managed such that the size would remain constant.