Free Astronomy Magazine September-October 2015

38 PLANETOLOGY With its mass and orbital position, Jupiter has always had a decisive role in the evolution of the planetary system architecture. Not only has it fostered the birth of a planet such as Earth, but it also appears to have indirectly con- tributed to making it liveable. Now astronomers have discovered an almost identical copy of Jupiter around a twin star of the Sun. Will there be more to come? Atwinof the system SEPTEMBER-OCTOBER 2015 A rtist’s view of the solar twin HIP 11915, and its Jupiter’s twin planet, HIP 11915 b. The distance between these two bodies is al- most identical to that between the Sun and Jupiter. [ESO/L. Benassi] by Michele Ferrara