Jupiter Will Become a Star One Day

Based upon current theories of stellar formation, Jupiter would need to become at the very least 70 times more massive to evolve into a star. Put in another way, about 70 Jupiter-like planets would have to be dumped into Jupiter in order for there to be sufficient material to create the internal temperatures and compression to allow thermonuclear fusion to take place. Jupiter is destined to continue slowly cooling like it has been for the past five billion years since its formation. Incidentally, the least massive of stars, about 70 times the mass of Jupiter, would have a diameter slightly smaller than Jupiter.

The Jovian Planets have Solid Surfaces / The Jovian Planets are Gas Giants

The Jovian, Jupiter-like planets, which also include Saturn, Uranus, and Neptune have extensive gaseous atmospheres which eventually become compressed into liquid oceans of primarily hydrogen and helium. As pressures increase, hydrogen is even forced into a metallic state which is the basis for creating the strong magnetic fields which surround all four Jovian worlds. It would be much better to describe these planets as liquid worlds with extensive gaseous atmospheres.