000178040 001__ 178040
000178040 005__ 20180317093724.0
000178040 0247_ $$2doi$$a10.1016/j.icarus.2011.09.015
000178040 02470 $$2ISI$$a000297568000016
000178040 037__ $$aARTICLE 000178040 245__$$aNIR spectral trends of HED meteorites: Can we discriminate between the magmatic evolution, mechanical mixing and observation geometry effects?
000178040 269__ $$a2011 000178040 260__$$c2011
000178040 336__ $$aJournal Articles 000178040 520__$$aThe Howardite-Eucrite-Diogenite (HED) suite is a family of differentiated meteorites that provide a unique opportunity to study the differentiation of small bodies. The likely parent-body of this meteorite group, (4) Vesta is presently under study by the Dawn mission, scrutinizing its surface in the visible and NIR infrared range. Here, we discuss how well the magmatic trends observed in HED might be retrieved from NIR spectroscopy, by studying laboratory spectra of 10 HED meteorites together with spectra from the RELAB database. We show that although an exsolution process did occur for most eucrites (i.e. decomposition of a primary calcic pyroxene into a high-Ca and low-Ca pyroxene), it does not affect the "bulk pyroxene" trend retrieved from the location of the pyroxene crystal field bands (Band I with a maximum of absorption around at about 1 mu m and Band II around 2 mu m). Absolute values of the chemical composition appears however to deviate from the expected chemical composition. We show that mechanical mixture (i.e. impact gardening) will produce a linear mixing in the pyroxenes band position diagram (Band I position vs Band II position). This diagram also reveals that howardite are not pure mixtures of an average eucrite and average diogenite. Because asteroid surfaces are expected to show topography, we also study the effect of observation geometry on the NIR spectra of an eucrite and a diogenite by measuring the bi-directional reflectance spectra from 0.4 to 4.6 mu m. Results show that these meteorites tend to act as forward scatterers, leading to a decrease of integrated band area (relative to the continuum) at high phase angles. The position of the two strong crystal field bands shows only small variability with observation geometry. Retrieval of the magmatic trends from the Band I vs Band II diagram should not be affected by observation geometry effects. Finally we performed NIR reflectance measurement on olivine diogenites. The presence of olivine can be suggested by using the Band Area Ratio vs Band I diagram, but this phase might affect the retrieval of pyroxene composition from the position of Band I and Band II. (C) 2011 Elsevier Inc. All rights reserved.
000178040 6531_ $$aMeteorites 000178040 6531_$$aAsteroid Vesta
000178040 6531_ $$aInfrared observations 000178040 6531_$$aAsteroids, Composition
000178040 6531_ $$aMineralogy 000178040 6531_$$aAsteroid 4 Vesta
000178040 6531_ $$aEucrite Parent Body 000178040 6531_$$aBidirectional Reflectance
000178040 6531_ $$aPlanetary Surfaces 000178040 6531_$$aPyroxene Mixtures
000178040 6531_ $$aSolar-System 000178040 6531_$$aNwa 2737
000178040 6531_ $$aDiogenites 000178040 6531_$$aGeochemistry
000178040 6531_ $$aIron 000178040 700__$$aBeck, P.$$uUJF Grenoble 1 CNRS INSU, Inst Planetol & Astrophys Grenoble IPAG UMR 5274, F-38041 Grenoble, France 000178040 700__$$aBarrat, J. -A.$$uUniv Brest, Univ Europeenne Bretagne, CNRS UMR Domaines Ocean 6538, IUEM, F-29280 Plouzane, France 000178040 700__$$aGrisolle, F.$$uUJF Grenoble 1 CNRS INSU, Inst Planetol & Astrophys Grenoble IPAG UMR 5274, F-38041 Grenoble, France 000178040 700__$$aQuirico, E.$$uUJF Grenoble 1 CNRS INSU, Inst Planetol & Astrophys Grenoble IPAG UMR 5274, F-38041 Grenoble, France 000178040 700__$$aSchmitt, B.$$uUJF Grenoble 1 CNRS INSU, Inst Planetol & Astrophys Grenoble IPAG UMR 5274, F-38041 Grenoble, France 000178040 700__$$aMoynier, F.$$uWashington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA 000178040 700__$$0244692$$aGillet, P.$$g199993$$uEcole Polytech Fed Lausanne, CH-1015 Lausanne, Switzerland 000178040 700__$$aBeck, C.$$uUniv Savoie, Inst Sci Terre, F-73376 Le Bourget Du Lac, France 000178040 773__$$j216$$q560-571$$tIcarus
000178040 909CO $$ooai:infoscience.tind.io:178040$$particle$$pSB 000178040 909C0$$0252407$$pEPSL 000178040 909c0$$xU12330
000178040 937__ $$aEPFL-ARTICLE-178040 000178040 973__$$aEPFL$$rREVIEWED$$sPUBLISHED
000178040 980__ aARTICLE