Jupiter's atmosphere—the first time astronomers had observed a collision between two objects in the Solar System. Other splitting comets include 3D/Biela
retain the "C" prefix for comets of periods larger than about 30 years until their return is confirmed. While Jupiter-familycomets are officially defined
is 624 Hektor. The Jupiterfamily is defined as comets that have a semi-major axis smaller than Jupiter's; most short-period comets belong to this group