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Elemental composition from gamma‐ray spectroscopy of the NEAR‐Shoemaker landing site on 433 Eros
Author(s) -
Evans Larry G.,
Starr Richard D.,
Brückner Johannes,
Reedy Robert C.,
Boynton William V.,
Trombka Jacob I.,
Goldsten John O.,
Masarik Jozef,
Nittler Larry R.,
Mccoy Timothy J.
Publication year - 2001
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2001.tb01854.x
Subject(s) - abundance (ecology) , spacecraft , composition (language) , spectroscopy , chemical composition , elemental analysis , spectrometer , analytical chemistry (journal) , physics , mineralogy , materials science , chemistry , astronomy , optics , environmental chemistry , linguistics , philosophy , organic chemistry , fishery , biology , thermodynamics
— Elemental composition and composition ratios derived from gamma‐ray measurements collected by the NEAR‐Shoemaker spacecraft while on the surface of 433 Eros are reported. Performance of the gamma‐ray spectrometer (GRS) during cruise and orbit is reviewed. The best gamma‐ray data were collected on the surface of Eros after the spacecraft's controlled descent on 2001 February 12. Methods used in spectral analysis, to convert peak areas to incident photons, and photons to elemental composition are described in some detail. The elemental abundance of K and the Mg/Si, Fe/Si, Si/O and Fe/O abundance ratios were determined. The Mg/Si and Si/O ratios and the K abundance are roughly chondritic, but the Fe/Si and Fe/O ratios are low compared to expected chondritic values. Three possible explanations for the apparent Fe depletion are considered.