Remote X-ray spectrometry for NEAR and future missions: Modeling and analyzing X-ray production from source to surface
P. E. Clark,J. I. Trombka +1 more
TLDR
In this article, the authors discuss the nature of such variations expected for missions to an asteroid, the Moon, and Mercury, and discuss an effective means of removing the effects of solar variability from surface measurements, as indicated by the agreement between theoretical models presented here and Apollo X-ray observations.Abstract:
Remote X-ray spectrometry will play a key role in the geochemical exploration of solar system bodies, provided the methodology for data analysis efficiently detects and removes solar source and flight trajectory-induced geometric variations. In this paper, we discuss the nature of such variations expected for missions to an asteroid, the Moon, and Mercury. An effective means of removing the effects of solar variability from surface measurements, as indicated by the agreement between theoretical models presented here and Apollo X-ray observations, is also discussed. We calculate X-ray spectra anticipated for these targets using probable surface compositions, solar outputs, and flight trajectories. Generally, the spectra show three distinctive regions where line intensities are clearly correlated with surface abundances: a high-energy Fe region, a moderate-energy Ca region, and a low-energy region which contains Mg, Al, and Si lines. In addition, we calculate anticipated integration times required for acceptable levels of certainty and estimate spatial resolutions achievable for those integration times for elements Mg, Al, Si, S, Ca, Ti, and Fe. Required integration times are lower (on the order of minutes or even seconds) and achievable spatial resolutions improved (on the order of kilometers) for the lower energy lines and for periods of higher solar activity. Using the Near Earth Asteroid Rendezvous (NEAR) mission to asteroid 433 Eros as an example, we describe a recommended approach for analysis of X-ray measurements based on our findings. Most importantly, we clearly demonstrate that major scientific goals for future exploration of asteroids, Mercury, and the Moon can be met by obtaining remote orbital X-ray measurements of these bodies.read more
Citations
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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
TL;DR: X-ray fluorescence spectra obtained by the MESSENGENGER spacecraft orbiting Mercury indicate that the planet's surface differs in composition from those of other terrestrial planets as discussed by the authors, and this observation, together with a low surface Fe abundance, supports the view that Mercury formed from highly reduced precursor materials, perhaps akin to enstatite chondrite meteorites or anhydrous cometary dust particles.
Journal ArticleDOI
Chemical heterogeneity on Mercury's surface revealed by the MESSENGER X-Ray Spectrometer
Shoshana Z. Weider,Larry R. Nittler,R. Starr,R. Starr,Timothy J. McCoy,Karen R. Stockstill-Cahill,Paul K. Byrne,Brett W. Denevi,James W. Head,Sean C. Solomon,Sean C. Solomon +10 more
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.
Journal ArticleDOI
Evidence for geochemical terranes on Mercury: Global mapping of major elements with MESSENGER's X-Ray Spectrometer
Shoshana Z. Weider,Larry R. Nittler,R. D. Starr,E. J. Crapster-Pregont,E. J. Crapster-Pregont,Patrick N. Peplowski,Brett W. Denevi,James W. Head,Paul K. Byrne,Paul K. Byrne,Steven A. Hauck,Denton S. Ebel,Denton S. Ebel,Sean C. Solomon,Sean C. Solomon +14 more
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).
Chemical heterogeneity on Mercury's surface revealed by the MESSENGER X-Ray Spectrometer
Shoshana Z. Weider,Larry R. Nittler,R. Starr,R. Starr,Timothy J. McCoy,Karen R. Stockstill-Cahill,Paul K. Byrne,Brett W. Denevi,James W. Head,Sean C. Solomon,Sean C. Solomon +10 more
TL;DR: In this article, 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.
Journal ArticleDOI
The elemental composition of asteroid 433 Eros: Results of the NEAR-Shoemaker X-ray spectrometer
J. Trombka,S. W. Squyres,J. Brückner,William V. Boynton,Robert C. Reedy,Timothy J. McCoy,P. Gorenstein,Larry G. Evans,James R. Arnold,R. D. Starr,Larry R. Nittler,M. E. Murphy,I. Mikheeva,Ralph L. McNutt,T. P. McClanahan,E. McCartney,John O. Goldsten,Robert E. Gold,S. R. Floyd,Pamela Elizabeth Clark,Thomas H. Burbine,J. S. Bhangoo,Samuel Bailey,M. Petaev +23 more
TL;DR: Major element composition ratios for regions of the asteroid 433 Eros imaged during two solar flares and quiet sun conditions during the period of May to July 2000 are reported.
References
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Journal ArticleDOI
Atomic form factors, incoherent scattering functions, and photon scattering cross sections
TL;DR: In this paper, the atomic form factor and the incoherent scattering function were derived from available state-of-the-art theoretical data, including the Pirenne formulas for Z=1, configuration-into-action results by Brown using Brown‐Fontana and Weiss correlated wavefunctions for Z =2 to 6 non-relativistic Hartree‐Fock results by Cromer for Z ≥ 0.005 A−1 to 109 A− 1, for all elements A=1 to 100.
Journal ArticleDOI
Scattering factors computed from relativistic Dirac–Slater wave functions
D. T. Cromer,J. T. Waber +1 more
Book
The Physics of Solar Flares
TL;DR: In this paper, the history of solar flare phenomena are examined in an introduction for advanced undergraduate and graduate physics students, with diagrams, graphs, and photographs of coronal mass ejections.
ReportDOI
Photon cross sections, attenuation coefficients, and energy absorption coefficients from 10 keV to 100 GeV
Book
Remote geochemical analysis : elemental and mineralogical composition
TL;DR: Remote geochemical analysis offers a powerful tool to study the elemental and mineralogical composition of our planet from its interior through to its atmosphere and to explore our solar system as mentioned in this paper, which has become possible because of major advances in sensor technology.
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