The mysterious comet 3I/ATLAS appears to be extremely large, making it orders of magnitude more massive than two other confirmed interstellar objects observed in our solar system in years past, a new study suggests.
Based on a new analysis of the most precise tracking data collected on the object since its discovery in July, the interstellar comet appears to be “anomalously massive,” a finding that raises new questions regarding our expectations about interstellar objects that occasionally traverse our solar system.
The research was detailed in a new paper by Richard Cloete, Peter Vere, and Harvard astronomer Avi Loeb, which places new limits on the object’s apparent non-gravitational acceleration and overall mass.
The new findings are largely consistent with existing upper estimates for the unusual space object’s size, with some recent observations suggesting it could be up to three miles long.
An “Anomalously Massive” Interstellar Object
More than four months of optical measurements collected on 3I/ATLAS, compiled by the Minor Planet Center, were used by the team for their analysis, which compared 3I/ATLAS’s position to the trajectory that would be expected based on gravity alone.
Based on their results, the team found almost no measurable deviation from a gravitational path, which seems to point to the fact that the interstellar comet is experiencing some degree of non-gravitational acceleration, albeit a negligible amount.
This finding would also seem to suggest that the object’s nucleus must possess a minimum diameter of roughly five kilometers (slightly more than three miles), which makes it several orders of magnitude more massive than the first two known interstellar objects, ʻOumuamua and Borisov.
Between May and September, more than 4,000 astrometric measurements related to the motion of 3I/ATLAS were collected from 227 observatories around the world. Based on this data, an upper limit on non-gravitational acceleration for the interstellar comet could be calculated, which was less than 15 meters per day squared.
According to the team’s study, this finding, with consideration for the principle of momentum conservation, suggests that gas jets produced on the surface of the object as it continues to be warmed by heat from the Sun should result in a measurable push. Based on current observations, however, the lack of detectable deviation exhibited by the object appears to imply that 3I/ATLAS is quite massive.
Hellbound and Down 