At the end of the film, 2010, Jupiter is seen to collapse on itself, becoming a low-luminosity star. Its icy moon Europa, warmed by the heat of its new Jupiter-Sun, surface melts, providing plenty of liquid water. Europa now becomes fertile ground for new life to form.
Could Jupiter ever become a Star?
Sadly, no. Jupiter is a mere 1/1000 the mass of the Sun. It's more than 80x too low in mass to drive hydrogen fusion reactions in its central core. However, Jupiter's interior is very warm. At near-infrared wavelengths Jupiter glows with about twice the temperature expected if just heated by the Sun. This is due to heat energy still contained from its original collapse and radioactive decay of heavy element in its core (like on Earth!).
Composition of Jupiter
About the same as the Sun: Mostly Hydrogen (~76%), Helium (~24%) and other trace elements (mostly C, N, O and Fe and most everything else in very low quantities). There is no real surface to Jupiter, instead its outer atmosphere just gets increasingly dense as we descend down into Jupiter, until it thickens into a dense liquid. Deep inside Jupiter the hydrogen is extremely hot (about 25,000 C), but is compressed to immense pressure, making it liquidy. At the very, very center, all of the heaviest elements (Fe, C, etc) have settled, giving it a small rocky central core, about the size of Earth.
Jupiter has a strong magnetic field, about 10x stronger than Earth's. It is maintained by Jupiter's liquidy hydrogen core and fast rotation. This creates an enormous magnetosphere, the region of space surrounding the planet in which the magnetic-field structure is strongly influenced by the intrinsic magnetic field of the planet.
The strong magnetosphere traps charged particles coming from the Sun's solar wind in a large torus (fat ring) around the planet. Some of the charged particles are funneled down into the polar regions, exciting an aurora like seen on Earth, when they hit the dense outer atmosphere of Jupiter.