John Hinrichs
Planetary Geosciences/HIGP

Title

"Temperature Dependence of the Intrinsic Near-IR Spectral Properties of
Meteorites and Lunar Soils"

Abstract

Spectral analysis of planetary bodies and asteroids in the infrared is a
primary tool for determining surface composition.  But, it has not been
widely recognized that spectra of many important asteroidal minerals vary
significantly with temperature.  These temperature dependent spectral
changes are intrinsic changes in the optical properties of the material and
are not due to thermal emission effects.  This has been demonstrated by
Roush and Singer and others with measurements emphasizing pure minerals.
New measurements of the temperature dependent spectral features of several
classes of meteorites and varied lunar soils have been made and will be
discussed.  In particular the sensitivity to temperature change as a
function of wavelength has been quantified for several HED meteorites
(believed to be from the asteroid 4 Vesta) as well as for a number of
ordinary chondrites (which may or may not be from S asteroids) and the
lunar maria (rich in mafic minerals).  The magnitude of the temperature
effect for complex mixtures in the form of meteorites and lunar soils shows
that for some objects this effect is important (asteroids) while for others
the effect might not be detectable (the Moon).