The beautiful terrain of the asteroid Benu. Credit: NASA’s Goddard Space Flight Center
Покритата със скали повърхност на астероид Бенну му осигурява защита от малки сблъсъци с метеорити, според сондажните наблюдения от[{”attribute=””>космическиякорабOSIRIS-REx(ПроизходспектралнаинтерпретацияидентификациянаресурсиSecurity-RegolithExplorer)наНАСАOSIRIS-RExпътувадоблизкиядоЗемятаастероидБеннуиносималкапробаобратнонаЗемятазаизследванеМисиятастартирана8септември2016готвоенновъздушнатастанцияКейпКанавералКосмическияткорабдостигнаБенупрез2018гищевърнепробанаЗемятапрез2023г[{”attribute=””>NASA’sOSIRIS-REx(OriginsSpectralInterpretationResourceIdentificationSecurity-RegolithExplorer)spacecraftOSIRIS-RExtraveledtonear-EarthasteroidBennuandisbringingasmallsamplebacktoEarthforstudyThemissionlaunchedonSeptember82016fromCapeFanaverationSanater[{”attribute=””>космическиякорабOSIRIS-REx(ПроизходспектралнаинтерпретацияидентификациянаресурсиSecurity-RegolithExplorer)наНАСАOSIRIS-RExпътувадоблизкиядоЗемятаастероидБеннуиносималкапробаобратнонаЗемятазаизследванеМисиятастартирана8септември2016готвоенновъздушнатастанцияКейпКанавералКосмическияткорабдостигнаБенупрез2018гищевърнепробанаЗемятапрез2023г[{”attribute=””>NASA’sOSIRIS-REx(OriginsSpectralInterpretationResourceIdentificationSecurity-RegolithExplorer)spacecraftOSIRIS-RExtraveledtonear-EarthasteroidBennuandisbringingasmallsamplebacktoEarthforstudyThemissionlaunchedonSeptember82016fromCapeCanaveralAirForceStationThespacecraftreachedBennuin2018andwillreturnasampletoEarthin2023
“These observations give a new insight into how asteroids like Benu react to energy impacts,” said Edward (Bo) Bierhaus of Lockheed Martin Space, Littleton, Colorado, lead author of an article published this month in Nature Geoscience.
Bennu is an asteroid with “ruins”, which means that it was formed from the wreckage of a much larger asteroid that was destroyed by an ancient impact. Fragments of the collision merged under their own weak gravity to form Bennu.
The team used unprecedented global high-resolution datasets to explore Bennu craters: images from the OSIRIS-REx camera suite and surface height data (topography) obtained from OSIRIS-REx Laser Altimeter, a laser leader. the spaceship.
This image shows the rocky surface of the asteroid Bennu. It was filmed by the PolyCam camera of NASA’s OSIRIS-REx spacecraft on April 11, 2019 from a distance of 2.8 miles (4.5 km). The field of view is 211 feet (64.4 m), and the large stone in the upper right corner of the image is 50 feet (15.4 m) high. When the image was taken, the spacecraft was above the southern hemisphere, directing the PolyCam far to the north and west. Credit: NASA / Goddard / University of Arizona
“Measuring the craters and their population in Bennu was extremely exciting,” said David Trang of the University of Hawaii at Manoa, Honolulu, co-author of the article. “At Bennu, we found something unique to small and rocky bodies that expanded our knowledge of impacts.”
Planetary scientists can estimate the age of surfaces by measuring the abundance and size of craters. Impact craters accumulate over time, so a surface with many craters is older than a surface with few craters. Also, the size of the crater depends on the size of the impact element, with larger impact elements usually creating larger craters. Because small meteoroids are much more abundant than large meteoroids, celestial objects such as asteroids usually have many more small craters than large ones.
The larger craters of Benu follow this pattern, as the number of craters decreases with increasing size. However, for craters smaller than about 6.6 to 9.8 feet (about 2-3 meters) in diameter, the trend is reversed, with the number of craters decreasing as their size decreases. This shows that something unusual is happening on the surface of Benu.
Researchers believe that the abundance of Bennu rocks acts as a shield, preventing the formation of craters on very small meteoroids. Instead, these blows are more likely to break stones or break them. In addition, some impact elements that manage to pass through the rocks make smaller craters than they would if Benu’s surface were covered with smaller, more uniform particles, such as beach sand.
This activity causes the Bennu surface to change differently from objects with fine-grained or hard surfaces. “The displacement or destruction of a single or small group of rocks by a small impact is perhaps one of the fastest-acting processes on the surface of an asteroid accumulated by rubble. With Bennu, this makes the surface look many times younger than the interior, ”said Bierhaus.
Reference: “Population of the asteroid crater (101955) Bennu shows impact armor and young surface” by EB Bierhaus, D. Trang, RT Daly, CA Bennett, OS Barnouin, KJ Walsh, R.-L. Ballouz, WF Bottke, KN Burke, ME Perry, ER Jawin, TJ McCoy, HC Connolly Jr., MG Daly, JP Dworkin, DN DellaGiustina, PL Gay, JI Brodbeck, J. Nolau, J. Padilla, S. Stewart, S Schwartz, P. Michel, M. Pajola and DS Lauretta, April 7, 2022, Nature Geoscience.DOI: 10.1038 / s41561-022-00914-5
More about the mission and the team:
The study is supported by NASA under the New Frontiers Program and the OSIRIS-REx Program for Scientists, the Canadian Space Agency, the French Space Agency, the Italian Space Agency, the European Union’s Horizon 2020 Research and Innovation Program and the Initiative’s Academies of Excellence. D ‘Excellence Joint, Excellent and dynamic initiative of the Université Côte d’Azur.
Dante Laureta of the University of Arizona, Tucson, is the principal investigator of OSIRIS-REx. The University of Arizona also led the OSIRIS-REx research team and planned scientific mission observation and data processing, and built the OSIRIS-REx Camera Suite. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and safety and security for OSIRIS-REx. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provided flight operations. The OSIRIS-REx laser altimeter was provided by the Canadian Space Agency. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s scientific missions directorate at NASA’s headquarters in Washington, DC
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