This picture reveals asteroid Bennu’s boulder-covered floor. 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 subject of view is 211 ft (64.4 m), and the massive boulder within the higher proper nook of the picture is 50 ft (15.4 m) tall. When the picture was taken, the spacecraft was over the southern hemisphere, pointing PolyCam far north and to the west. Credit: NASA/Goddard/University of Arizona
Asteroid Bennu’s boulder-covered floor offers it safety towards small meteoroid impacts, in keeping with observations of craters by NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) spacecraft.
“These observations give new perception into how asteroids like Bennu reply to energetic impacts,” stated Edward (Beau) Bierhaus of Lockheed Martin Space, Littleton, Colorado, lead creator of a paper revealed on this month’s challenge of Nature Geoscience.
Bennu is a “rubble-pile” asteroid, which means that it fashioned from the particles of a a lot bigger asteroid that was destroyed by an historic affect. Fragments from the collision coalesced below their very own weak gravity to kind Bennu.
The staff used unprecedented, high-resolution international information units to look at craters on Bennu: photos from the OSIRIS-REx Camera Suite and surface-height information (topography) derived from the OSIRIS-REx Laser Altimeter, a laser-ranging (lidar) instrument on the spacecraft.
“Measuring craters and their inhabitants on Bennu was exceptionally thrilling,” stated David Trang of the University of Hawaii at Mānoa, Honolulu, a co-author of the paper. “At Bennu, we found one thing distinctive to small and rocky our bodies, which expanded our information of impacts.”
Planetary scientists can estimate the age of surfaces by measuring the abundance and sizes of craters. Impact craters accumulate over time, so a floor with many craters is older than a floor with few craters. Also, the scale of the crater will depend on the scale of the impactor, with bigger impactors usually making bigger craters. Because small meteoroids are way more plentiful than massive meteoroids, celestial objects like asteroids normally have many extra small craters than massive ones.
Bennu’s bigger craters comply with this sample, with the numbers of craters reducing as their dimension will increase. However, for craters smaller than about 6.6 to 9.8 toes (round 2–3 meters) in diameter, the development is backwards, with the variety of craters reducing as their dimension decreases. This signifies one thing uncommon is occurring on Bennu’s floor.
The researchers assume that Bennu’s profusion of boulders acts as a defend, stopping many small meteoroids from forming craters. Instead, these impacts usually tend to break aside the boulders or chip and fracture them. Also, some impactors that do make it via the boulders make smaller craters than they’d if Bennu’s floor was lined in smaller, extra uniform particles, like seaside sand.
This exercise causes the floor of Bennu to vary in a different way than objects with fine-grained or stable surfaces. “The displacement or disruption of a person or small group of boulders by a small affect might be one of the fast-acting processes on a rubble-pile asteroid’s floor. On Bennu, this contributes to creating the floor seem like many instances youthful than the inside,” stated Bierhaus.
Studying craters on asteroid Bennu reveals how lengthy it has been orbiting close to Earth
More data:
E. B. Bierhaus et al, Crater inhabitants on asteroid (101955) Bennu signifies affect armouring and a younger floor, Nature Geoscience (2022). DOI: 10.1038/s41561-022-00914-5
Provided by
NASA’s Goddard Space Flight Center
Citation:
NASA spacecraft observes asteroid Bennu’s boulder ‘physique armor’ (2022, June 16)
retrieved 16 June 2022
from https://phys.org/information/2022-06-nasa-spacecraft-asteroid-bennu-boulder.html
This doc is topic to copyright. Apart from any truthful dealing for the aim of personal examine or analysis, no
half could also be reproduced with out the written permission. The content material is offered for data functions solely.