Rubble pile asteroids are forever.
| Autor: | Jourdan F; Western Australian Argon Isotope Facility and TIGeR, Curtin University, Bentley WA 6102, Australia.; John de Laeter Centre, Curtin University, Bentley WA 6102, Australia.; Space Science and Technology Centre & School of Earth and Planetary Sciences, Curtin University, Bentley WA 6102, Australia., Timms NE; Space Science and Technology Centre & School of Earth and Planetary Sciences, Curtin University, Bentley WA 6102, Australia., Nakamura T; Laboratory for Early Solar System Evolution, Department of Earth Science, Graduate School of Science, Tohoku University Aoba, Sendai, 980-8578 Japan., Rickard WDA; John de Laeter Centre, Curtin University, Bentley WA 6102, Australia., Mayers C; John de Laeter Centre, Curtin University, Bentley WA 6102, Australia., Reddy SM; Space Science and Technology Centre & School of Earth and Planetary Sciences, Curtin University, Bentley WA 6102, Australia., Saxey D; John de Laeter Centre, Curtin University, Bentley WA 6102, Australia., Daly L; School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK.; Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney 2006 NSW, Australia.; Department of Materials, University of Oxford, Oxford OX1 3PH, Great Britain., Bland PA; Space Science and Technology Centre & School of Earth and Planetary Sciences, Curtin University, Bentley WA 6102, Australia., Eroglu E; School of Molecular and Life Sciences, Curtin University, Bentley WA 6102, Australia., Fougerouse D; John de Laeter Centre, Curtin University, Bentley WA 6102, Australia.; Space Science and Technology Centre & School of Earth and Planetary Sciences, Curtin University, Bentley WA 6102, Australia. |
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| Jazyk: | angličtina |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2023 Jan 31; Vol. 120 (5), pp. e2214353120. Date of Electronic Publication: 2023 Jan 23. |
| DOI: | 10.1073/pnas.2214353120 |
| Abstrakt: | Rubble piles asteroids consist of reassembled fragments from shattered monolithic asteroids and are much more abundant than previously thought in the solar system. Although monolithic asteroids that are a kilometer in diameter have been predicted to have a lifespan of few 100 million years, it is currently not known how durable rubble pile asteroids are. Here, we show that rubble pile asteroids can survive ambient solar system bombardment processes for extremely long periods and potentially 10 times longer than their monolith counterparts. We studied three regolith dust particles recovered by the Hayabusa space probe from the rubble pile asteroid 25143 Itokawa using electron backscatter diffraction, time-of-flight secondary ion mass spectrometry, atom probe tomography, and 40 Ar/ 39 Ar dating techniques. Our results show that the particles have only been affected by shock pressure of ca. 5 to 15 GPa. Two particles have 40 Ar/ 39 Ar ages of 4,219 ± 35 and 4,149 ± 41 My and when combined with thermal and diffusion models; these results constrain the formation age of the rubble pile structure to ≥4.2 billion years ago. Such a long survival time for an asteroid is attributed to the shock-absorbent nature of rubble pile material and suggests that rubble piles are hard to destroy once they are created. Our results suggest that rubble piles are probably more abundant in the asteroid belt than previously thought and provide constrain to help develop mitigation strategies to prevent asteroid collisions with Earth. |
| Databáze: | MEDLINE |
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