Nereid May Be Neptune's Last Survivor From a Violent Moonpocalypse

A Science Advances study suggests Neptune’s largest moon Triton captured into the planet’s system and wiped out the original moon family, leaving Nereid as a possible native survivor with a highly elongated orbit. JWST infrared data imply Nereid is more like an icy native moon than a captured Kuiper Belt Object, challenging its status as a former KBO. REBOUND simulations show that in about 20% of runs, Triton can eject an inner moon into a long, tilted orbit similar to Nereid’s, implying Nereid could be a frozen relic of Neptune’s violent moon history; confirmation would require a future spacecraft visit.