ORCID Profile
0000-0002-2020-3476
Current Organisation
Jacobs / NASA Johnson Space Center
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Publisher: Research Square Platform LLC
Date: 16-03-2023
DOI: 10.21203/RS.3.RS-2389559/V1
Abstract: Volatile components are abundant in carbonaceous asteroids and can be important tracers for the evolution of asteroid surfaces interacting with the space environment, but their behavior on airless surfaces is poorly understood. S les from the C-type carbonaceous asteroid Ryugu show dehydration of phyllosilicate, indicating ongoing surface modifications on the aqueously-altered asteroid. Here we report the analysis of Ryugu s les showing selective liberation of carbon, oxygen, and sulfur from iron-rich oxide, sulfide, and carbonate, which are major products of aqueous alteration. These mineral surfaces are decomposed to metallic iron, iron nitride, and magnesium-iron oxide. The modifications are most likely caused by solar wind implantation and micrometeorite impacts and are distinct indicators of surface space exposure over 10 3 years. Nitridation of metallic iron may require micrometeorites rich in solid nitrogen compounds, which implies that the amount of nitrogen available for planetary formation in the inner solar system is larger than previously recognized.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Springer Science and Business Media LLC
Date: 07-08-1900
DOI: 10.1038/S41550-022-01841-6
Abstract: Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of s les from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe 3+ to Fe 2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss.
Location: United States of America
No related grants have been discovered for Brittany Cymes.