NASA spacecraft observes asteroid Bennu’s ‘bulletproof vest’

This picture reveals the rock-covered floor of asteroid Bennu. It was taken by the PolyCam digicam 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 ft (64.4 m) and the big rock within the higher proper nook of the picture is 50 ft (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 meteoroid 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,” stated Edward (Beau) Bierhaus of Lockheed Martin Area, Littleton, Colorado, lead writer of a paper printed on this month’s subject. from nature geoscience.

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

The workforce used unprecedented high-resolution world datasets to look at Bennu’s craters: photographs from the OSIRIS-REx digicam suite and floor peak (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,” stated 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. Influence craters accumulate over time, so a floor with many craters is older than a floor with few craters. Additionally, the scale of the crater will depend on the scale of the impactor, with bigger impactors typically creating bigger craters. As a result of small meteoroids are way more considerable than massive meteoroids, celestial objects like asteroids usually 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. Nonetheless, for craters smaller than about 6.6 to 9.8 ft (about 2 to three meters) in diameter, the pattern is reversed, with the variety of craters lowering as their measurement decreases. This means that one thing uncommon is going on on the floor of Bennu.

The researchers imagine Bennu’s profusion of boulders acts as a protect, stopping many small meteoroids from forming craters. As an alternative, 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 lined with smaller, extra uniform particles, corresponding to seaside sand.

This exercise causes Bennu’s floor to alter otherwise from objects with fine-grained or strong surfaces. “The displacement or disruption of a person or small group of rocks by a small impression 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 stated.

Examine of craters on asteroid Bennu reveals how lengthy it has been orbiting close to Earth

Extra info:
EB Bierhaus et al, Crater inhabitants on asteroid (101955) Bennu signifies impression 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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