Jupiter

Jupiter is a planet located in our solar system. It is a gas giant with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined.It would have become a star if it were a 50 times heavier. Jupiter's atmosphere is mainly hydrogen and helium, which stars are made of.

Internal structure
Jupiter was expected to either consist of a dense core, a surrounding layer of liquid metallic hydrogen (with some helium) extending outward to about 78% of the radius of the planet.

Atmosphere
Jupiter's upper atmosphere is composed of 3 layers that are 71 km high together, with the top having clouds of ammonia ice, middle having ammonium hydrosulfide and innermost layer having water, ice and water vapor. Rest is made out of primarily hydrogen and helium.