A new study by researchers in France and Japan has shown that high-velocity impacts disguise the surface of metal-rich asteroids, coating them in glassy material and masking their true composition. This result, detailed in Science Advances, may explain why telescopic observations reveal many fewer asteroids with surfaces consistent with metal than would be expected based on spectral evidence.
Many small celestial bodies appear to have developed metallic cores early in the history of the Solar System, leading scientists to expect a significant number of asteroids produced from high-velocity impacts with these objects to have metal-rich compositions. To better understand the inherent properties of metal-rich asteroids, the researchers, led by Guy Libourel and Patrick Michel of the Université Côte d’Azur in Nice conducted a series of 11 high-velocity (3.39 and 6.89 km/s) impact experiments in the laboratory using steel and iron meteorite targets as proxies for asteroid surfaces. They found that the meteorites presented completely different compositions post-impact because of the combined effects of crater shape, changes in surface roughness, and a silicate glass coating produced by melting material in the meteorites during impact. These results led them to posit that many metal-rich asteroids may be covered by craters with similar characteristics. The 2026 NASA Psyche mission—the first opportunity for a detailed, close-up study of a metallic asteroid— will allow these ideas to be tested.
Read the research paper: Hypervelocity impacts as a source of deceiving surface signatures on iron-rich asteroids by G. Libourel et al. Science Advances 10.1126/sciadv.aav3971
For a news story on this work, please email: firstname.lastname@example.org