Centaur in Transition: 450P/LONEOS Begins the Move Toward Becoming a Comet

Astronomers watching centaur 450P/LONEOS—a body orbiting beyond Jupiter—have observed the onset of comet-like activity, with a developing coma detected by Gemini North. JWST spectroscopy shows carbon dioxide driving the activity and hints of crystalline ice, but no water vapor. The object’s orbit was reshaped by Saturn’s gravity in the past, placing its perihelion just beyond Jupiter, and continued planetary nudges could push it into a Jupiter-family comet, helping link centaurs to active comets; findings are set for Planetary Science Journal (arXiv).