The discovery could challenge our theories of how gas giants like Jupiter form. A dark planet passes in front of a bright red star. Artist's conception of a large gas giant planet orbiting a small red dwarf star called TOI-5205. (Image credit: Katherine Cain, courtesy of the Carnegie Institution for Science) Astronomers have discovered an unusual planetary system consisting of a Jupiter-sized planet orbiting a tiny star that is only four times the size of the solar system gas giant. This "forbidden" configuration of a massive planet orbiting a relatively tiny star could challenge theories of how gas giant planets...