Space.com and the University of Central Florida report that the coma around 450P/LONEOS became more visible from 2019 to 2024. Webb spectra showed carbon dioxide, but no water-vapour or carbon-monoxide feature. The direct arXiv study combines Gemini North imaging with Webb measurements. The findings support carbon-dioxide outgassing as the activity source at this distance, but concern a single centaur.
Space.com and the University of Central Florida report that Gemini North images showed the gas-and-dust coma around 450P/LONEOS becoming more visible between 2019 and 2024. The James Webb Space Telescope examined the coma's composition with spectroscopy. The direct arXiv preprint combines these observing lines to characterize the nucleus and coma of a small active centaur; the results have not yet appeared in final peer-reviewed form.[1], [2]
Webb observations found a carbon-dioxide gas distribution in the coma and no emission feature from water vapour or carbon monoxide. Space.com and UCF say the nucleus is too cold at this distance for ordinary water ice to sublimate efficiently. The team therefore interprets carbon dioxide as the main volatile feeding the observed coma. A possible crystalline-water-ice signal suggests that some ice may have undergone thermal or physical processing.[1], [2]
Tracing the orbit backward shows that 450P/LONEOS passed about 4.6 million kilometres from Saturn in 1992. The sources report that this encounter shortened the orbit and moved perihelion to 5.4 astronomical units, exposing the object to more solar heating. That sequence supplies a plausible physical context for the activity; one object cannot establish the same path for every centaur.[1], [2]
