Thermal fatigue as the origin of regolith on small asteroids.
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| Title: | Thermal fatigue as the origin of regolith on small asteroids. |
|---|---|
| Authors: | Delbo, Marco, Libourel, Guy, Wilkerson, Justin, Murdoch, Naomi, Michel, Patrick, Ramesh, K. T., Ganino, Clément, Verati, Chrystele, Marchi, Simone |
| Source: | Nature. 4/10/2014, Vol. 508 Issue 7495, p233-236. 4p. 1 Color Photograph, 3 Diagrams, 1 Chart, 8 Graphs. |
| Subjects: | Thermal fatigue, Regolith, Meteoroids, Near-earth asteroids, Weathering |
| Abstract: | Space missions and thermal infrared observations have shown that small asteroids (kilometre-sized or smaller) are covered by a layer of centimetre-sized or smaller particles, which constitute the regolith. Regolith generation has traditionally been attributed to the fall back of impact ejecta and by the break-up of boulders by micrometeoroid impact. Laboratory experiments and impact models, however, show that crater ejecta velocities are typically greater than several tens of centimetres per second, which corresponds to the gravitational escape velocity of kilometre-sized asteroids. Therefore, impact debris cannot be the main source of regolith on small asteroids. Here we report that thermal fatigue, a mechanism of rock weathering and fragmentation with no subsequent ejection, is the dominant process governing regolith generation on small asteroids. We find that thermal fragmentation induced by the diurnal temperature variations breaks up rocks larger than a few centimetres more quickly than do micrometeoroid impacts. Because thermal fragmentation is independent of asteroid size, this process can also contribute to regolith production on larger asteroids. Production of fresh regolith originating in thermal fatigue fragmentation may be an important process for the rejuvenation of the surfaces of near-Earth asteroids, and may explain the observed lack of low-perihelion, carbonaceous, near-Earth asteroids. [ABSTRACT FROM AUTHOR] |
| Copyright of Nature is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Psychology and Behavioral Sciences Collection |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
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| Header | DbId: pbh DbLabel: Psychology and Behavioral Sciences Collection An: 95516931 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Thermal fatigue as the origin of regolith on small asteroids. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Delbo%2C+Marco%22">Delbo, Marco</searchLink><br /><searchLink fieldCode="AR" term="%22Libourel%2C+Guy%22">Libourel, Guy</searchLink><br /><searchLink fieldCode="AR" term="%22Wilkerson%2C+Justin%22">Wilkerson, Justin</searchLink><br /><searchLink fieldCode="AR" term="%22Murdoch%2C+Naomi%22">Murdoch, Naomi</searchLink><br /><searchLink fieldCode="AR" term="%22Michel%2C+Patrick%22">Michel, Patrick</searchLink><br /><searchLink fieldCode="AR" term="%22Ramesh%2C+K%2E+T%2E%22">Ramesh, K. T.</searchLink><br /><searchLink fieldCode="AR" term="%22Ganino%2C+Clément%22">Ganino, Clément</searchLink><br /><searchLink fieldCode="AR" term="%22Verati%2C+Chrystele%22">Verati, Chrystele</searchLink><br /><searchLink fieldCode="AR" term="%22Marchi%2C+Simone%22">Marchi, Simone</searchLink> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Nature%22">Nature</searchLink>. 4/10/2014, Vol. 508 Issue 7495, p233-236. 4p. 1 Color Photograph, 3 Diagrams, 1 Chart, 8 Graphs. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Thermal+fatigue%22">Thermal fatigue</searchLink><br /><searchLink fieldCode="DE" term="%22Regolith%22">Regolith</searchLink><br /><searchLink fieldCode="DE" term="%22Meteoroids%22">Meteoroids</searchLink><br /><searchLink fieldCode="DE" term="%22Near-earth+asteroids%22">Near-earth asteroids</searchLink><br /><searchLink fieldCode="DE" term="%22Weathering%22">Weathering</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Space missions and thermal infrared observations have shown that small asteroids (kilometre-sized or smaller) are covered by a layer of centimetre-sized or smaller particles, which constitute the regolith. Regolith generation has traditionally been attributed to the fall back of impact ejecta and by the break-up of boulders by micrometeoroid impact. Laboratory experiments and impact models, however, show that crater ejecta velocities are typically greater than several tens of centimetres per second, which corresponds to the gravitational escape velocity of kilometre-sized asteroids. Therefore, impact debris cannot be the main source of regolith on small asteroids. Here we report that thermal fatigue, a mechanism of rock weathering and fragmentation with no subsequent ejection, is the dominant process governing regolith generation on small asteroids. We find that thermal fragmentation induced by the diurnal temperature variations breaks up rocks larger than a few centimetres more quickly than do micrometeoroid impacts. Because thermal fragmentation is independent of asteroid size, this process can also contribute to regolith production on larger asteroids. Production of fresh regolith originating in thermal fatigue fragmentation may be an important process for the rejuvenation of the surfaces of near-Earth asteroids, and may explain the observed lack of low-perihelion, carbonaceous, near-Earth asteroids. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Nature is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1038/nature13153 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 4 StartPage: 233 Subjects: – SubjectFull: Thermal fatigue Type: general – SubjectFull: Regolith Type: general – SubjectFull: Meteoroids Type: general – SubjectFull: Near-earth asteroids Type: general – SubjectFull: Weathering Type: general Titles: – TitleFull: Thermal fatigue as the origin of regolith on small asteroids. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Delbo, Marco – PersonEntity: Name: NameFull: Libourel, Guy – PersonEntity: Name: NameFull: Wilkerson, Justin – PersonEntity: Name: NameFull: Murdoch, Naomi – PersonEntity: Name: NameFull: Michel, Patrick – PersonEntity: Name: NameFull: Ramesh, K. T. – PersonEntity: Name: NameFull: Ganino, Clément – PersonEntity: Name: NameFull: Verati, Chrystele – PersonEntity: Name: NameFull: Marchi, Simone IsPartOfRelationships: – BibEntity: Dates: – D: 10 M: 04 Text: 4/10/2014 Type: published Y: 2014 Identifiers: – Type: issn-print Value: 00280836 Numbering: – Type: volume Value: 508 – Type: issue Value: 7495 Titles: – TitleFull: Nature Type: main |
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