Webb Space Telescope Detects Record-Size Asteroid  

ESA's Illustration of New Asteroid

On February 6th, 2023, The European Space Agency announced the record-breaking discovery of the smallest known asteroid in the asteroid belt. Measuring under one kilometer wide, the James Webb Space Telescope detected the asteroid “completely unexpectedly” while undergoing calibration tests.

James Webb Space Telescope:

 Launched on Christmas day, 2021, the James Webb Space Telescope (JWST) is the most advanced and complex telescope to ever be constructed and flown to space. Unlike its predecessor, JWST does not fly in a standard earth orbit, but instead is in a ‘Lagrange Point’. While the Hubble Space Telescope was designed to act as the Jack of all Trades space telescope, being able to focus on a wide variety of wavelengths, JWST is specializing on just the Infrared band of wavelength.

Detection and Cataloging:

During a routine calibration test of the Mid Infrared Instrument (MIRI) camera onboard James Webb, the space telescope detected an asteroid that shortly interrupted the data collection. The calibration test was using a standard asteroid first discovered in 1998 to test onboard systems to calibrate the telescope. However, during the tracking of the asteroid, what appeared to be a glitch or failure occurred as the telescope returned erroneous brightness and positioning levels. Upon review, researchers noticed that a smaller object had passed between the telescope and the asteroid. Using the short pass of the asteroid, researchers were able to develop new techniques for determining the orbit, size, and speed of the new asteroid just based on the limited information discerned from the telescope. 

“Our results show that even ‘failed’ Webb observations can be scientifically useful, if you have the right mindset and a little bit of luck. Our detection lies in the main asteroid belt, but Webb's incredible sensitivity made it possible to see this roughly 100-meter object at a distance of more than 100 million kilometers.” 

-Thomas Müller, Max Planck Institute for Extraterrestrial Physics.

Despite being very prevalent in our solar system, small asteroids have received very little research due to the technological challenge of tracking and cataloging asteroids of such small sizes. JWST and its research teams unknowingly have created a more efficient way of tracking these asteroids, and could encourage more effort and research into the study of these smaller asteroids. Knowing more about these asteroids could better detail how our solar system began, and give more insight into the composition of our solar system at large.