Nereid: Neptune’s Last Moon After Triton’s Ancient Arrival

Using Webb telescope data and simulations, scientists propose that Neptune’s moon Nereid is the sole survivor of an ancient, Triton-triggered disruption of Neptune’s original moon system; Triton’s capture likely destroyed the other moons, while Nereid was hurled outward into a highly eccentric, distant orbit. Its water-rich surface and Uranian-like signature support its status as the last remnant of Neptune’s early lunar family.