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| Titel |
Geologic mapping of the Av-2 Bellicia quadrangle of asteroid 4 Vesta |
| VerfasserIn |
O. Ruesch, H. Hiesinger, N. Schmedemann, T. Kneissl, D. T. Blewett, D. A. Williams, C. T. Russell, C. A. Raymond |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250066840
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| Zusammenfassung |
| One of the largest asteroids in the Main Belt, the asteroid Vesta, is currently observed by the Dawn spacecraft [1]. In contrast to previously in-situ explored asteroids [2-7] Vesta is most probably an intact protoplanet and spectroscopic observations suggest a basaltic nature for its crust [8]. The Dawn Framing Camera [9] has acquired visible images that allow geologic mapping of its surface. Within the Dawn Mapping Working Group we focused on the north-eastern quadrangle (21° N-60° N and 0° E-90° E). Unfortunately, illumination conditions limited the observation from 21° N to 45° N and only with low incidence angle. The morphology of the study area is characterized by impact craters and smooth ejecta blankets typical for the northern hemisphere of Vesta. Using a lunar-like production function and chronology function [10], the crater size-frequency distribution (CSFD) indicates an old surface age with possible resurfacing events. A distinctive pattern in the CSFD for <10km craters is observed, but to fully understand its origin, further investigations are needed. Dark-rayed ejecta are observed, and overall distinctive albedo features are rare when compared to the equatorial terrains. For the study area we find that the visible-NIR spectral measurements, characterized by pyroxenes absorption bands [11], are neither related to volcanic/magmatic morphologic features (e.g., lava flows, dykes) nor to albedo features. Instead, the pyroxene signatures are associated with an old, cratered surface with a homogeneous albedo.
[1] Russell et al., (2007) Earth Moon Planets, 10. [2] Carr et al., (1994) Icarus 107, 61-71. [3] Thomas et al., (1999) Icarus 140, 17-27. [4] Robinson et al., (2002) M&PS 37, 1651-1684. [5] Sullivan et al., (1996) Icarus 120,119-139. [6] Fujiwara et al., (2006) Science 312,1330. [7] Sierks et al., (2011) Science 334, 487. [8] Pieters et al., (2011) Space Sci. Rev. [9] Sierks et al., (2011) Space Sci Rev. [10] Neukum et al., (2011) EPSC-DPS2011-501-1. [11] Coradini et al., (2011) EPSC-DPS2011-740-6. |
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