When you buy through links on our articles, Future and its syndication partners may earn a commission.A remote hot Jupiter exoplanet has foregone the typical solitary life that worlds of its kind normally lead, in favor of companionship with another planet — and now, astronomers think they know why.Hot Jupiters are gas giants that orbit exceedingly close to their star. However, they don’t form that close, but are rather assembled much farther out before migrating inward. When they make that trip, they usually kick out any other planets in their way — but the hot Jupiter TOI-1130c seems to have latched onto a smaller planet as a traveling companion. The two seem to have migrated towards their star together.AdvertisementAdvertisementThe TOI-1130 system is located 190 light-years away and was found by Chelsea Huang of the University of South Queensland, who spotted the system in 2020 when sifting through data from NASA’s Transiting Exoplanet Survey Satellite (TESS) while at the Massachusetts Institute of Technology (MIT).”This was a one-of-a-kind system,” said Huang in a statement. “Hot Jupiters are ‘lonely’, meaning that they don’t have companion planets inside their orbits. They are so massive and their gravity so strong, that whatever is inside their orbit just gets scattered away. But somehow, with this hot Jupiter, an inner companion has survived, and that raises questions about how such a system could form.”Now an international team of astronomers led by MIT’s Saugata Barat and including Huang think they have found the answer by bringing the James Webb Space Telescope (JWST) to bear on the hot Jupiter’s companion, which is a mini-Neptune type world three-and-a-half times the diameter of Earth and catalogued as TOI-1130b. By observing the system when the mini-Neptune was transiting its star, they were able to search for where the planet’s atmosphere was absorbing the star’s light. The wavelengths of light being absorbed told them that the planet sports a “heavy” atmosphere full of water vapor, carbon dioxide, sulfur dioxide and signs of methane. In this context, “heavy” means heav …
