In fact, while methane is a atmospheric characteristic of giant gas planets like Jupiter, the only brown dwarf found to even have a trace of methane was Gliese 229 B, which orbits a reddish, M - class dwarf located about 20 light - years away from Earth. (members.nova.org)
Of the alien solar systems we've spotted, many seem to have one intriguing thing in common: giant gas planets like Jupiter and Saturn orbiting very close to their parent star. (sciencemag.org)
The existence of a fifth giant gas planet at the time of the Solar System's formation — in addition to Jupiter, Saturn, Uranus and Neptune that we know of today — was first proposed in 2011. (sciencedaily.com)