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Mineralogical Mapping of the Av-8 Marcia and Av-9 Numisia Quadrangles of Asteroid 4 Vesta

Capaccioni, F. and De Sanctis, M.C. and Nathues, A. and Ammannito, E. and Tosi, F. and Zambon, F. and Palomba, E. and Frigeri, A. and Le Corre, L. and Reddy, V. and Jaumann, R. and Stephan, K. and Preusker, Frank and Denevi, B. and McCord, T. B. (2012) Mineralogical Mapping of the Av-8 Marcia and Av-9 Numisia Quadrangles of Asteroid 4 Vesta. In: Copernicus. EGU 2012, 22.04-27.04.2012, Wien, Österreich.



Asteroid 4 Vesta is currently observed by NASA's Dawn orbiter. The Dawn Team is conducting mineralogical mapping of the surface in the form of 15 quadrangle maps, and here we report results from the mapping of the two adjacent quadrangles Marcia (Av-8) and Numisia (Av-9). The mapping is based on a Framing Camera (FC) color band ratio and Visible and InfraRed (VIR) hyperspectral images. Av-8 Marcia Quadrangle covers 144˚-216˚E longitude while Av-9 Numisia extends from 216˚-288˚E longitude; both quadrangles are located in the equatorial region from ±21˚ latitude. Av-8 Marcia is dominated by a cratered regions, which is a low-albedo ejecta field containing craters Marcia, (68 km by 58 km), Calpurnia (54 km by 52 km), and Minucia (26 km by 23 km). A hill with a dark-rayed crater, named Aricia Tholus, is also nearby (size about 42.5 km and 28 km). Av-9 Numisia is dominated by Vestalia Terra, a distinct region of Vesta. Many of the impact craters in Av-9 have both bright and dark layers in their walls and also distinct ejecta lobes. The largest feature in Av-9 is the 33 km diameter Numisia crater which is centrally located at 7°S, 247°E. The other significant feature is the 15 km diameter Cornelia crater. Cornelia, smaller than Numisia is apparently more interesting has it shows a greater color diversity and an extensive ray system. In particular FC color data show an inner dark albedo region surrounded by an extended light colored ray system, this is also shown in the VIR images. Both FC color ratio images and VIR images show compositional variations within the Marcia quadrangle (De Sanctis et al., LPSC2012). The band depth distribution is uneven in this region and associated with the geological structures present in the quadrangles. On average the dominant terrains are the so called ET ( Equatorial Terrains) characterized by intermediate band depths, but associated with Marcia we see also terrains with very deep band depth similar to the ST (Southern Terrains) and deep band depth as the MLT (Mid Latitude Terrains). The low albedo ejecta field, derived from the Marcia and Calpurnia craters (located in Av-9), mantles underlying older terrains and is associated with the CET (Copious ejecta Terrains): the band depth are very shallow. VIR data show strong 1 µm and 2 µm absorptions exposed within the walls and floor of impact crater Marcia, suggesting excavation of pyroxene-rich material and/or variations in particle sizes. FC color ratio images, as well as VIR color ratio (Red:750/430 nm; Green :750/920 nm; Blue:430/750 nm) show color differences in Marcia and Calpurnia. The color and spectral data show the difference between the eastern side of the Marcia and Calpurnia ejecta field from its western side. Moreover it appears an unusual diffuse deposit surrounding an unnamed crater on the western side of the quadrangle. Further study is underway to investigate the significance of these color variations. The authors gratefully acknowledge the support of the Dawn Instrument, Operations, and Science Teams. This work is supported by an Italian Space Agency (ASI) grant and by NASA through the Dawn project and a Dawn at Vesta Participating Scientist grant.

Item URL in elib:https://elib.dlr.de/80567/
Document Type:Conference or Workshop Item (UNSPECIFIED)
Title:Mineralogical Mapping of the Av-8 Marcia and Av-9 Numisia Quadrangles of Asteroid 4 Vesta
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
De Sanctis, M.C.Istituto Nazionale di Astrofisica, Rome, Italy.UNSPECIFIED
Nathues, A.Max-Planck Institute for Solar System Research, Katlenburg-Lindau, GermanyUNSPECIFIED
Ammannito, E.INAF, Istituto di Fisica Dello Spazio Interplanetario, Roma, ItalyUNSPECIFIED
Tosi, F.INAF-IASF Istituto di Astrofisica Spaziale e Fisica Cosmica, Roma ItalyUNSPECIFIED
Zambon, F.INAF-IAPS, Via del Fosso del Cavaliere 100, I-00133 Rome, ItalyUNSPECIFIED
Palomba, E.Institute for Interplanetary Space Physics - INAF, Rome, ItalyUNSPECIFIED
Frigeri, A.National Institute of Astrophysics, Rome, ItalyUNSPECIFIED
Le Corre, L.Max Planck Institute for Solar System Research, Max-Planck-Str. 2, Katlenburg-Lindau, 37191, GermanyUNSPECIFIED
Reddy, V.Department of Space Studies, University of North Dakota, Grand Forks, ND 58202, USAUNSPECIFIED
Jaumann, R.ralf.jaumann (at) dlr.deUNSPECIFIED
Stephan, K.katrin.stephan (at) dlr.deUNSPECIFIED
Preusker, Frankfrank.preusker (at) dlr.deUNSPECIFIED
Denevi, B.Johns Hopkins University Applied Physics Laboratory 11100 Johns Hopkins Rd. Laurel, MD 20723-6099, USAUNSPECIFIED
McCord, T. B.HIGP/SOEST, University of Hawaii, Winthrop, WA, USAUNSPECIFIED
Date:April 2012
Journal or Publication Title:Copernicus
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:No
Keywords:Vesta, Dawn
Event Title:EGU 2012
Event Location:Wien, Österreich
Event Type:international Conference
Event Dates:22.04-27.04.2012
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Space Exploration
DLR - Research theme (Project):R - Project DAWN
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Geology
Deposited By: Aydin, Zeynep
Deposited On:11 Jan 2013 14:39
Last Modified:31 Jul 2019 19:39

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