Mineralogical interpretation of reflectance spectra of Eros from NEAR near-infrared spectrometer low phase flyby

Lucy A. McFadden, Dennis D. Wellnitz, Matthew Schnaubelt, Michael J. Gaffey, J. F. Bell, Noam Izenberg, Scott Murchie, Clark R. Chapman

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


High signal-to-noise near-infrared spectrometer (NIS) spectra acquired during the low phase flyby of the near-Earth asteroid rendezvous (NEAR) mission to 433 Eros are analyzed to determine mineral chemistry and proportions of mafic silicates across the asteroid's surface at 2.68 × 5.50 km spatial resolution. Spectral band parameters are derived, and compared with those of laboratory samples of known mineral composition, grain size distribution and terrestrial, meteoritic and lunar pyroxene spectral properties. The NIS derived band parameters are consistent with ordinary chondrite meteorites. We invoke the presence of a clinopyroxene component in the spectra, which is consistent with ordinary chondrite mineralogy and/or some degree of partial melting of ordinary chondritic material. Spectra measured across the surface of Eros can reveal small but real spectral variations. Most relative spectra are uniform to within 1-2%. Some areas suggest compositional variations of a few percent. Spectral slope variations of a few percent are seen indicating a non-uniform distribution of materials affecting the slope parameter but with no resolved absorption bands. We find no correlation of slope with viewing geometry or compositional variation. The band parameter values do not consistently indicate a specific ordinary chondrite class but Eros is definitely undifferentiated with possible compositional variations of no more than 1-2%.

Original languageEnglish (US)
Pages (from-to)1711-1726
Number of pages16
JournalMeteoritics and Planetary Science
Issue number12
StatePublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science


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