New Webb Telescope photobombs asteroids

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The James Webb Space Telescope has observed its smallest cosmic object yet – a previously unknown asteroid the size of Rome’s Colosseum.

A team of European astronomers has spotted the space rock, which is between 328 and 656 feet (100 to 200 meters) long, and located in the main asteroid belt between Mars and Jupiter.

The donut-shaped belt is home to most of the solar system’s asteroids. The main asteroid belt is in close alignment with the ecliptic plane, or the same plane that comprises Earth’s orbit around the sun.

The asteroid may be one of the smallest ever found in the Main Belt. These small, dark cosmic objects are incredibly difficult to observe, but astronomers can use Webb to search for other asteroids of this size in the future.

Further observations will help astronomers learn more about the asteroid in the future and confirm that it is truly a newly discovered object.

The detection of the asteroid was made by chance when the Webb research team focused the telescope’s Mid-InfraRed Instrument, or MIRI, on the main-belt asteroid (10920) 1998 BC1, discovered at the originated in 1998, to take calibration images.

“We have – completely unexpectedly – detected a small asteroid in publicly available MIRI calibration observations,” Thomas Müller, an astronomer at the Max Planck Institute for Extraterrestrial Physics in Germany, said in a statement. “The measurements are among the first MIRI measurements targeting the ecliptic plane and our work suggests that many new objects will be detected with this instrument.”

Asteroids are the remnants of the formation of the solar system, and astronomers have determined the location of more than 1.1 million of them.

Many asteroids still remain unknown – and Webb’s discovery hints that the powerful infrared telescope could uncover many other small rocky objects that would otherwise have escaped detection before.

Calibration images taken by Webb’s research team during their attempt to observe asteroid (10920) 1998 BC1 did not go as planned and were deemed a technical failure as the object appeared so brilliant.

The astronomers were still able to use the data to test a new technique for determining an asteroid’s orbit and size. Observations from (10920) 1998 BC1 were combined with data from the European Space Agency’s Gaia mission and ground-based telescopes.

While analyzing the data, the researchers spotted an “intruder” in their observations – the new asteroid making its first appearance.

“Our results show that even Webb’s ‘failed’ observations can be scientifically useful, if you have the right mindset and a bit of luck,” Müller said. “Our detection is in the main asteroid belt, but Webb’s incredible sensitivity allowed us to see this object about 100 meters away from a distance of over 100 million kilometers.”

And astronomers won’t be surprised if other unknown space rocks photobomb future Webb images.

“This is a fantastic result that highlights MIRI’s abilities to serendipitously detect a previously undetectable asteroid size in the main belt,” said Bryan Holler, Webb Support Scientist at the Space Telescope Science Institute in Baltimore, in a statement. “Repeats of these observations are being scheduled, and we fully expect new intruding asteroids in these images!”