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Bidirectional visible‐NIR and biconical FT‐IR reflectance spectra of Almahata Sitta meteorite samples
Author(s) -
HIROI Takahiro,
JENNISKENS Peter,
BISHOP Janice L.,
SHATIR Tahani S. M.,
KUDODA Ayman M.,
SHADDAD Muawia H.
Publication year - 2010
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.1945-5100.2010.01097.x
Subject(s) - asteroid , meteorite , regolith , space weathering , astrobiology , albedo (alchemy) , geology , chondrite , spectral line , parent body , mineralogy , astronomy , physics , art , performance art , art history
– Bidirectional visible and near‐infrared and off‐axis biconical Fourier transform infrared reflectance spectra of Almahata Sitta meteorite stone samples, fragments of asteroid 2008 TC 3 , have been measured. These meteorites represent the first freshly fallen polymict ureilites available for such studies. Although the chip samples show varying degrees of terrestrial weathering depending on their environment on Earth, many of them are much fresher than other ureilites known to date. The majority of the Almahata Sitta chips studied here show only a weak near‐UV absorption, a flat spectrum at visible and near‐IR wavelengths, and varying depths of the 1 and 2 μm pyroxene and olivine bands. The astronomical reflectance observations of the asteroid 2008 TC 3 over the range 0.55–1.0 μm provide a constraint on what a combination of the measured spectra can represent in the surface reflectance of the asteroid over the 0.32–2.55 μm range measured in this study. Most of the recovered samples of Almahata Sitta have textures and albedos similar to stones #27 (largest recovered fragment), #4, and #47. Results of linear least‐square fits of the asteroid 2008 TC 3 spectrum with two sets of the meteorite spectra suggest that the asteroid had 10–12% albedo and no fine regolith on its surface. We note that other lithologies may be at the surface of other fragments of the asteroid family from which 2008 TC 3 originated. In that case, reflectance spectra could vary significantly among family members.