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Although 60558 Echeclus and 2014 YX49 are both classified as centaur objects—outer solar system bodies in unstable orbits—they exhibit striking differences in _____ object 60558 Echeclus is considered an active centaur, showing sporadic comet-like activity (such as clouds of dust and gas on its surface), 2014 YX49, showing no such activity, is considered dormant.