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Abstract<\/h2>\n
Space erosion from dust impacts may set upper limits on the cosmic ray exposure (CRE) ages of stony meteorites. A meteoroid orbiting within the asteroid belt is bombarded by both cosmic rays and interplanetary dust particles. Galactic cosmic rays penetrate only the first few meters of the meteoroid; deeper regions are shielded. The dust particle impacts create tiny craters on the meteoroid\u2019s surface, eroding it away by abrasion at a particular rate. Hence a particular point inside a meteoroid accumulates cosmic ray products only until that point wears away, limiting CRE ages. The results would apply to other regolith-free surfaces in the solar system as well, so that abrasion may set upper CRE age limits which depend on the dusty environment. Calculations based on N. Divine\u2019s dust populations and on micrometeoroid cratering indicate that large stony meteoroids in circular ecliptic orbits at 2 AU will record 21<\/sup>Ne CRE ages of \u223c176 \u00d7 106<\/sup> years if dust masses are in the range 10-21<\/sup> \u2013 10-3<\/sup> kg. This is in broad agreement with the maximum observed CRE ages of \u223c100 \u00d7 106<\/sup> years for stones. High erosion rates in the inner solar system may limit the CRE ages of Near-Earth Asteroids (NEAs) to \u223c120 \u00d7 106<\/sup> years. A characteristic of erosion is that the neon concentrations tend to rise as the surface of the meteorite is approached, rather than drop off as for meteorites with fixed radii. Pristine samples recovered from space may show the rise. If the abrasion rate for stones were a factor of \u223c6 larger than found here, then the ages would drop into the 30 \u00d7 106<\/sup> y range, so that abrasion alone might be able to explain many CRE ages. However, there is no strong evidence for higher abrasion rates, and in any case would probably not be fast enough to explain the youngest ages of 0.1 – 1 \u00d7 106<\/sup> y. Further, space erosion is much too slow to explain the \u223c600 \u00d7 106<\/sup> y ages of iron meteorites.<\/p>\n<\/div>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"David Parry Rubincam LINK Abstract Space erosion from dust impacts may set upper limits on the cosmic ray exposure (CRE) ages of stony meteorites. A meteoroid orbiting within the asteroid belt is bombarded by both…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[69,96,8],"tags":[1849,153],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/219"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=219"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/219\/revisions"}],"predecessor-version":[{"id":220,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/219\/revisions\/220"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=219"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=219"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=219"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}