Archive – Asteroid – UA – File
Dec. 9 () –
MIT astronomers have found a way to detect asteroids around 10 meters in diameter within the main asteroid belt between Mars and Jupiter.
Until now, the smallest asteroids that scientists could discern there were about a kilometer in diameter. With the team’s new approach, scientists can now detect asteroids in the main belt as small as 10 meters in diameter.
In an article published in ‘Nature’ magazine The researchers report that they have used their method to detect more than 100 new one-decameter asteroids in the main asteroid belt. The space rocks range from the size of a bus to several stadiums across, and are the smallest asteroids within the main belt that have been detected to date. The researchers envision that this approach could be used to identify and track asteroids that are likely to approach Earth.
It is estimated that the asteroid that extinct the dinosaurs was about 10 kilometers in diameter, about the width of Brooklyn. An impact of this magnitude is expected to hit Earth rarely, once every 100 to 500 million years. In contrast, much smaller asteroids, the size of a bus, can collide with Earth more frequently, every few years. These “decameter” asteroids, which measure just a few tens of meters in diameter, they are more likely to escape the main asteroid belt and migrate toward it to become near-Earth objects.
IMPACT OF 1908 IN TUNGUSKA
If they impact, these small but powerful space rocks can send shock waves through entire regions, such as the 1908 impact in Tunguska, Siberia, and the 2013 asteroid that disintegrated in the sky over Chelyabinsk, Urals. Being able to observe decameter asteroids from the main belt would provide a window into the origin of meteorites.
Now, co-authors of the study, including MIT planetary science professors Julien de Wit and Richard Binzel, say: “We have been able to detect near-Earth objects up to 10 meters in size when they are really close to Earth. Now We have a way to detect these small asteroids when they are much further away, so we can perform more precise orbital trackingwhich is key to planetary defense.”
De Wit and his team mainly focus on the search and study of exoplanets, worlds outside the solar system that could be habitable. The researchers are part of the group that in 2016 discovered a planetary system around TRAPPIST-1, a star located about 40 light years from Earth. Using the Transiting and Planetismal Small Telescope (TRAPPIST) in Chile, the team confirmed that the star hosts Earth-sized rocky planets, several of which are in the habitable zone.
Since then, scientists have focused many telescopes at different wavelengths on the TRAPPIST-1 system to better characterize the planets and search for signs of life. With these searches, astronomers have had to sift through the “noise” in telescope images, such as gas, dust and planetary objects found between Earth and the star, to more clearly decipher the planets of TRAPPIST-1. Often the noise they discard includes asteroids passing nearby. “For most astronomers, asteroids are seen as a kind of plague of the sky, in the sense that they cross the field of view and affect the data,” says de Wit.
De Wit and Burdanov wondered if the same data used to search for exoplanets could be recycled and mined to find asteroids in our own solar system. To do this, they looked for the method of “shifting and stacking”, an image processing technique that was first developed in the 1990s. The method involves shifting multiple images of the same field of view and stacking them to see if an otherwise faint object can overshadow the noise.
Applying this method to search for unknown asteroids in images that are originally focused on distant stars would require significant computational resources, as it would involve testing a large number of scenarios to determine where an asteroid might be. Researchers would then have to change thousands of images for each scenario to see if an asteroid is really where it was predicted to be.
For the new study, researchers looked for more, but smaller, asteroids using data from the world’s most powerful observatory: NASA’s James Webb Space Telescope (JWST). which is especially sensitive to infrared light rather than visible light. In reality, asteroids orbiting in the main asteroid belt are much brighter at infrared wavelengths than at visible wavelengths and are therefore much easier to detect with the JWST’s infrared capabilities.
The team applied their approach to images of TRAPPIST-1 obtained by JWST. The data comprised more than 10,000 images of the star, which were originally obtained to search for signs of atmospheres around the system’s inner planets. After processing the images, the researchers were able to detect eight known asteroids in the main belt. They then searched deeper and discovered 138 new asteroids around the main belt, all with a diameter of tens of meters, the smallest main belt asteroids detected to date. They suspect that some asteroids are on their way to becoming near-Earth objects, while one is probably a Trojan, an asteroid that follows Jupiter.
“We thought we would only detect a few new objects, but we have detected many more than expected, especially the small ones” says de Wit. “It is a sign that we are investigating a new population regime, in which many more small objects are formed through cascades of collisions that are very efficient at disintegrating asteroids below 100 meters.”
“We are entering a totally new and unexplored space thanks to modern technologies,” says Burdanov. “It’s a good example of what we can do as a field when we look at data differently. Sometimes there are big rewards, and this is one of them.”
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