They detect the smallest object observed with the Webb Space Telescope

Illustration of an asteroid / NASA

Science | Space

The asteroid measures around 100-200 meters in diameter and was discovered 'by chance'

Elena Martin Lopez

The James Webb Space Telescope (JWST) continues to expand our knowledge of the universe. It has been with this tool that an international team of European astronomers has detected an extremely 'small' and hitherto unknown asteroid. It measures between 100 and 200 meters in diameter (a football field measures about 107 m) and is located in the main asteroid belt, located between Mars and Jupiter. It is probably the smallest object observed by this telescope, as NASA has announced in a statement, and its detection has important implications for understanding the formation and evolution of the Solar System, although the US agency considers that more are needed. observations to better characterize its nature and properties.

The uptake of the asteroid was "totally unexpected," said Thomas Müller, an astronomer at the Max Planck Institute for Extraterrestrial Physics (Germany). It happened while the researchers were calibrating the MIRI Instrument (Mid-InfraRed Instrument, for its acronym in English) of the telescope. "The measurements are some of the first by MIRI directed at the ecliptic plane and our work suggests that many new objects will be detected with this instrument," added Müller.

The Webb observations that revealed this finding were not originally designed to capture new asteroids, but rather were made to test the performance of some of MIRI's filters in observing another asteroid discovered in 1998. At the conclusion of their analysis, the scientists they considered that something had gone wrong, but that was when they detected the small asteroid. Therefore, Müller believes "that even the failed Webb observations can be scientifically useful, if you have the right frame of mind and a bit of luck," Müller explained.

More groundbreaking discoveries

The Solar System is replete with asteroids and small rocky bodies: astronomers currently know of more than 1.1 million of these remnants from the early days of the Solar System. JWST's ability to explore these objects at infrared wavelengths is expected to lead to groundbreaking new scientific discoveries. “To be able to detect a body like this with the largest ground-based optical telescopes available, it would take more than an hour of observations. However, with the Webb, the object is visible after a few minutes of observation", said Toni Santana-Ros, a researcher at the Institute of Physics Applied to Sciences and Technologies of the University of Alicante (UA) and co-author of the work. . Müller added: "Webb's incredible sensitivity made it possible to see this object of about 100 meters at a distance of more than 100 million kilometers."