Astronomers observed the early stages of 450P/LONEOS’s transformation into a comet as it orbits the Sun beyond Jupiter. Discovered by Lowell Observatory in 2004 and located between Jupiter and Neptune, 450P belongs to the “centaur” class, a term generally used for inactive icy bodies. The team, led by planetary scientist Charles Schambeau of the University of Central Florida, determined that a cloud of gas and dust known as a coma had formed around the object’s solid nucleus. The cloud was recorded as gradually brightening between 2019 and 2024, while 450P reached its closest position to the Sun in August 2024. Because of its approximately 22-year orbital period, the object is not yet considered a Jupiter-family comet.
Orbital calculations showed that 450P passed within approximately 4.6 million kilometers of Saturn in 1992 and that this encounter reduced its closest distance to the Sun to 813 million kilometers. The increased heat released its ices and trapped gases, forming the coma. The James Webb Space Telescope detected carbon dioxide in the cloud. Scientists say that if the activity continues, 450P could eventually become a short-period comet.
Why it matters
This observation provides a direct example of how objects in the centaur class, generally considered passive, can become active. It thus makes it possible to observe the process by which comets develop from icy bodies located farther from the Sun. The fact that the past close passage by Saturn altered the orbit shows that planets can affect the heating conditions of small bodies and the activity associated with them. While the James Webb Space Telescope’s detection of carbon dioxide provides data on the composition of the coma and the mechanism by which the ices are exposed, the key question that remains open is whether this activity will continue and which class 450P will belong to.
Background
Saturn is not a new name in the FikirPilot archive: we published a news report mentioning it in the last 90 days; that article is dated September 3, 2026.