Jupiter-like exoplanets that are blisteringly close to their parent stars were long thought to be friendless in their cosmic neighborhood. A new study has now revealed that many of them might, in fact, have planetary companions.
Astronomers thought that most hot Jupiters, exoplanets that are at least as massive as Jupiter but circle their stars in 10 days or less, and their cousins warm Jupiters that orbit their stars within 10 days are solitary residents in their star systems. The astronomers thought that the enormous gravity of these gas giants tossed other planets out of the star systems after these giants formed and migrated toward their stars. Until recently, observations supported this theory.
