The object, detected by the international team of European astronomers, is likely the smallest observed to date by Webb, according to Nasa's statement.
“We — completely unexpectedly — detected a small asteroid in publicly available MIRI calibration observations," said Thomas Müller, an astronomer at the Max Planck Institute for Extraterrestrial Physics in Germany.
In the course of the analysis, the researchers found the smaller interloper in the same field of view. It said that the object measures 100–200 meters, occupies a very low-inclination orbit, and was located in the inner main-belt region at the time of the Webb observations.
The team's project used data from the calibration of the Mid-InfraRed Instrument (MIRI), in which the team serendipitously detected an interloping asteroid, the research published in the journal Astronomy and Astrophysics said.
According to the research, these Webb observations were not designed to hunt for new asteroids - in fact, they were calibration images of the main belt asteroid (10920) 1998 BC1, which astronomers discovered in 1998.
Calibration is the act of checking or adjusting the accuracy of a measuring instrument by comparison with a standard.
"Our detection lies in the main asteroid belt, but Webb's incredible sensitivity made it possible to see this roughly 100-metre object at a distance of more than 100 million kilometers," the researcher said.
According to the research, current models predict the occurrence of asteroids down to very small sizes, but small asteroids have been studied in less detail than their larger counterparts owing to the difficulty of observing these objects. Future dedicated Webb observations will allow astronomers to study asteroids smaller than 1 kilometer in size, NASA said.
This result also suggested that Webb will also be able to serendipitously contribute to the detection of new asteroids.
