Abstract

Understanding the true nature of extra-terrestrial water and organic matter that were present at the birth of our solar system, and their subsequent evolution, necessitates the study of pristine astromaterials. In this study, we have studied both the water and organic contents from a dust particle recovered from the surface of near-Earth asteroid 25143 Itokawa by the Hayabusa mission, which was the first mission that brought pristine asteroidal materials to Earth’s astromaterial collection. The organic matter is presented as both nanocrystalline graphite and disordered polyaromatic carbon with high D/H and 15N/14N ratios (δD =  + 4868 ± 2288‰; δ15N =  + 344 ± 20‰) signifying an explicit extra-terrestrial origin. The contrasting organic feature (graphitic and disordered) substantiates the rubble-pile asteroid model of Itokawa, and offers support for material mixing in the asteroid belt that occurred in scales from small dust infall to catastrophic impacts of large asteroidal parent bodies. Our analysis of Itokawa water indicates that the asteroid has incorporated D-poor water ice at the abundance on par with inner solar system bodies. The asteroid was metamorphosed and dehydrated on the formerly large asteroid, and was subsequently evolved via late-stage hydration, modified by D-enriched exogenous organics and water derived from a carbonaceous parent body.

Details

Title
Organic matter and water from asteroid Itokawa
Author
Chan, Q H, S 1 ; Stephant, A 2 ; Franchi, I A 2 ; Zhao, X 2 ; Brunetto, R 3 ; Kebukawa, Y 4 ; Noguchi, T 5 ; Johnson, D 6 ; Price, M C 7 ; Harriss, K H 7 ; Zolensky, M E 8 ; Grady, M M 9 

 Royal Holloway University of London, Department of Earth Sciences, Egham, UK (GRID:grid.4970.a) (ISNI:0000 0001 2188 881X); The Open University, Milton Keynes, UK (GRID:grid.10837.3d) (ISNI:0000000096069301) 
 The Open University, Milton Keynes, UK (GRID:grid.10837.3d) (ISNI:0000000096069301) 
 Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, Orsay, France (GRID:grid.460789.4) (ISNI:0000 0004 4910 6535) 
 Yokohama National University, Yokohama, Japan (GRID:grid.268446.a) (ISNI:0000 0001 2185 8709) 
 Kyushu University 744, Faculty of Arts and Science, Fukuoka, Japan (GRID:grid.177174.3) (ISNI:0000 0001 2242 4849) 
 The Open University, Milton Keynes, UK (GRID:grid.10837.3d) (ISNI:0000000096069301); University of Exeter, Penryn, Camborne School of Mines, Cornwall, UK (GRID:grid.8391.3) (ISNI:0000 0004 1936 8024) 
 University of Kent, CAPS, School of Physical Sciences, Canterbury, UK (GRID:grid.9759.2) (ISNI:0000 0001 2232 2818) 
 NASA Johnson Space Center, Astromaterials Research and Exploration Science, Houston, USA (GRID:grid.419085.1) (ISNI:0000 0004 0613 2864) 
 The Open University, Milton Keynes, UK (GRID:grid.10837.3d) (ISNI:0000000096069301); The Natural History Museum, London, UK (GRID:grid.35937.3b) (ISNI:0000 0001 2270 9879) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2496264480
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.