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Photometric behavior of spectral parameters in Vesta dark and bright regions as inferred by the Dawn VIR spectrometer

Longobardo, Andrea and Palomba, Ernesto and Capaccioni, Fabrizio and De Sanctis, Maria Cristina and Tosi, Federico and Ammannito, Eleonora and Schröder, Stefan E. and Zambon, Francesca and Raymond, Carol A. and Russell, Christopher T. (2014) Photometric behavior of spectral parameters in Vesta dark and bright regions as inferred by the Dawn VIR spectrometer. Icarus, 240, pp. 20-35. Elsevier. DOI: 10.1016/j.icarus.2014.02.014 ISSN 0019-1035

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Official URL: http://dx.doi.org/10.1016/j.icarus.2014.02.014

Abstract

NASA’s Dawn spacecraft orbited Vesta for approximately one year, collecting thousands of hyperspectral images of its surface. The mission revealed that Vesta’s surface shows the largest variations in surface albedo on asteroids visited thus far, due to the presence of dark and bright materials at the local scale (i.e. 0.1–10 km). The aim of this work is to characterize the photometric properties of bright and dark regions, and thus derive and apply an empirical photometric correction to all the hyperspectral observations of Vesta. The very large dataset (i.e. more than 20 million spectra) provided by the VIR imaging spectrometer onboard Dawn enabled accurate statistical analysis of the spectral dataset, aimed at retrieving empirical relations between several spectral parameters (i.e. visible and infrared reflectance, band depths, band centers, Band Area Ratio) and the illumination/viewing angles. The derived relations made it possible to derive photometrically corrected maps of these spectral parameters and to infer information on the regolith shadowing effect in the Vestan dark and bright regions. As an additional analysis, we also evaluated the correlation between surface temperature and band center position. A general conclusion of this analysis is that, from a photometric point of view, the distinction between bright and dark material units lies mainly in the larger contribution due to multiple scattering in the bright units. We observed reflectance and band depth variations over Vesta’s entire surface, but these variations were much larger in the dark regions than in the bright ones. Band centers have been found to shift to longer wavelengths at increasing temperatures, with a trend that is the same observed for HED meteorites (Reddy et al. [2012]. Icarus 217, 153–158). Finally, the Band Area Ratio (i.e. the ratio between areas of the main pyroxene absorption bands located at 1.9 μm and at 0.9 μm, respectively) did not show any dependence on observational geometry, again a behavior similar to laboratory results obtained on HED meteorites (Reddy et al. [2012]. Icarus 217, 153–158).

Item URL in elib:https://elib.dlr.de/89782/
Document Type:Article
Title:Photometric behavior of spectral parameters in Vesta dark and bright regions as inferred by the Dawn VIR spectrometer
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Longobardo, AndreaINAF Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere, 00133 Rome, ItalyUNSPECIFIED
Palomba, ErnestoINAF Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere, 00133 Rome, ItalyUNSPECIFIED
Capaccioni, FabrizioINAF-IAPSUNSPECIFIED
De Sanctis, Maria CristinaIstituto Nazionale di Astrofisica, Rome, Italy.UNSPECIFIED
Tosi, FedericoInstituto di Fisica dello Spazio Interplanetario, Consiglio Nazionale delle Richerche, Rome 00133, ItalyUNSPECIFIED
Ammannito, EleonoraINAF-IAPSUNSPECIFIED
Schröder, Stefan E.stefanus.schroeder (at) dlr.deUNSPECIFIED
Zambon, FrancescaINAF Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere, 00133 Rome, ItalyUNSPECIFIED
Raymond, Carol A.Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States.UNSPECIFIED
Russell, Christopher T.UCLA, Los Angeles, CA, United States.UNSPECIFIED
Date:2014
Journal or Publication Title:Icarus
Refereed publication:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:240
DOI :10.1016/j.icarus.2014.02.014
Page Range:pp. 20-35
Publisher:Elsevier
ISSN:0019-1035
Status:Published
Keywords:Asteroid Vesta; Asteroids, surfaces; Photometry; Spectroscopy
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Projekt DAWN
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Geology
Deposited By: Schröder, Dr. Stefan
Deposited On:25 Aug 2014 13:35
Last Modified:10 Jan 2019 15:54

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