NASA spacecraft observes asteroid Bennu’s ‘bulletproof vest’

This picture exhibits the rock-covered floor of asteroid Bennu. It was taken by the PolyCam digital camera on NASA’s OSIRIS-REx spacecraft on April 11, 2019 from a distance of two.8 miles (4.5 km). The sector of view is 211 toes (64.4 m) and the massive rock within the higher proper nook of the picture is 50 toes (15.4 m) excessive. When the picture was taken, the spacecraft was over the southern hemisphere, pointing PolyCam far north and west. Credit score: NASA/Goddard/College of Arizona

Asteroid Bennu’s boulder-covered floor provides it safety from small meteor impacts, in accordance with crater observations by NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Useful resource Identification, Safety-Regolith Explorer) spacecraft .

“These observations present new perception into how asteroids like Bennu reply to energetic impacts,” mentioned Edward (Beau) Bierhaus of Lockheed Martin Area, Littleton, Colorado, lead creator of a paper revealed on this month’s difficulty. from nature geoscience.

Bennu is a “rubble pile” asteroid, which means it shaped from the particles of a a lot bigger asteroid that was destroyed by an historical affect. The fragments from the collision coalesced beneath their low gravity to kind Bennu.

The crew used unprecedented high-resolution world datasets to look at Bennu’s craters: photos from the OSIRIS-REx digital camera suite and floor top (topography) information derived from the OSIRIS- REx, a laser ranging instrument (lidar). on the spaceship.

“Measuring craters and their inhabitants on Bennu was exceptionally thrilling,” mentioned David Trang of the College of Hawaii at Mānoa, Honolulu, co-author of the paper. “At Bennu, we found one thing distinctive with small, rocky our bodies, which broadened our data of the impacts.”

Planetary scientists can estimate the age of surfaces by measuring the abundance and measurement of craters. Impression craters accumulate over time, so a floor with many craters is older than a floor with few craters. Additionally, the dimensions of the crater depends upon the dimensions of the impactor, with bigger impactors usually creating bigger craters. As a result of small meteoroids are rather more plentiful than massive meteoroids, celestial objects like asteroids sometimes have many extra small craters than massive ones.

Bennu’s largest craters observe this sample, with the variety of craters lowering as their measurement will increase. Nevertheless, for craters lower than about 6.6 to 9.8 toes (about 2 to three meters) in diameter, the development is reversed, with the variety of craters lowering as their measurement decreases. This means that one thing uncommon is occurring on the floor of Bennu.

The researchers consider Bennu’s profusion of boulders acts as a protect, stopping many small meteoroids from forming craters. As a substitute, these impacts usually tend to shatter rocks or chip and fracture them. Moreover, some rock-cutting impactors create smaller craters than they might if Bennu’s floor had been coated with smaller, extra uniform particles, similar to seaside sand.

This exercise causes Bennu’s floor to alter in a different way from fine-grained or solid-surface objects. “The displacement or disruption of a person or small group of rocks by a small affect might be one of many quickest processes on the floor of a rubblepile asteroid. On Bennu, this contributes to make the floor a lot youthful than the inside,” Bierhaus mentioned.

Research of craters on asteroid Bennu exhibits how lengthy it has been orbiting close to Earth

Extra info:
EB Bierhaus et al, Crater inhabitants on asteroid (101955) Bennu signifies affect shielding and a younger floor, nature geoscience (2022). DOI: 10.1038/s41561-022-00914-5

Supplied by NASA’s Goddard Area Flight Middle

Quote: NASA spacecraft observes ‘bulletproof vest’ from asteroid Bennu (Jun 16, 2022) Retrieved June 17, 2022 from -bennu-boulder.html

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