X‐ray fluorescence measurements of the surface elemental composition of asteroid 433 Eros
Larry R. Nittler,R. D. Starr,Lucy F. Lim,Timothy J. McCoy,Thomas H. Burbine,Robert C. Reedy,Jacob I. Trombka,Paul Gorenstein,Steven W. Squyres,William V. Boynton,T. McClanahan,Jesse S. Bhangoo,Pamela Elizabeth Clark,M. E. Murphy,Rosemary V. Killen +14 more
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In this paper, the major element ratios determined for the S-class asteroid 433 Eros using remote-sensing x-ray fluorescence spectroscopy with the near-Earth asteroid rendezvous Shoemaker X-ray spectrometer (XRS).Abstract:
We report major element ratios determined for the S-class asteroid 433 Eros using remote- sensing x-ray fluorescence spectroscopy with the near-Earth asteroid rendezvous Shoemaker x-ray spectrometer (XRS). Data analysis techniques and systematic errors are described in detail. Data acquired during five solar flares and during two extended "quiet Sun" periods are presented; these results sample a representative portion of the asteroid's surface. Although systematic uncertainties are potentially large, the most internally consistent and plausible interpretation of the data is that Eros has primitive Mg/Si, Al/Si, Ca/Si and Fe/Si ratios, closely similar to H or R chondrites. Global differentiation of the asteroid is ruled out. The S/Si ratio is much lower than that of chondrites, probably reflecting impact-induced volatilization and/or photo- or ion-induced sputtering of sulfur at the surface of the asteroid. An alternative explanation for the low S/Si ratio is that it reflects a limited degree of melting with loss of an FeS-rich partial melt. Size-sorting processes could lead to segregation of Fe-Ni metal from silicates within the regolith of Eros; this could indicate that the Fe/Si ratios determined by the x-ray spectrometer are not representative of the bulk Eros composition.read more
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The Major-Element Composition of Mercury’s Surface from MESSENGER X-ray Spectrometry
Larry R. Nittler,R. D. Starr,Shoshana Z. Weider,Timothy J. McCoy,William V. Boynton,Denton S. Ebel,Carolyn M. Ernst,Larry G. Evans,John O. Goldsten,D. K. Hamara,David J. Lawrence,Ralph L. McNutt,C. E. Schlemm,Sean C. Solomon,Ann L. Sprague +14 more
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Meteoritic parent bodies: Their number and identification
TL;DR: In this paper, the spectral properties of asteroids are used to link asteroids with particular meteorite groups due to the number of asteroids with similar spectral properties and the uncertainties in the optical, chemical, and physical properties of the asteroid regolith.
Journal ArticleDOI
Chemical heterogeneity on Mercury's surface revealed by the MESSENGER X-Ray Spectrometer
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TL;DR: In this paper, the analysis of 205 spatially resolved measurements of the surface composition of Mercury from MESSENGER's X-Ray Spectrometer is presented, and the surface footprints of these measurements are categorized according to geological terrain.
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TL;DR: In this article, the major-element composition of the surface of Mercury was mapped from orbital MESSENGER X-Ray Spectrometer measurements, and the results revealed highly variable compositions (e.g., Mg/Si and Al/Si range over 0.1 − 0.8 and 0.4, respectively).
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