ON THE POSSIBILITY OF ASTEROID MATTER COMPOSITION ESTIMATION NEAR PERIHELION

Abstract

Two programs in the MATLAB environment for studying chemical and mineralogical composition of asteroids from their visible-range reflectance spectra were previously developed by us. The first one is used for estimation of mineral composition of the asteroid surface matter on the basis of spectral characteristics of known meteorite and mineral analog samples. The second
program allows estimation of a taxonomic class of an asteroid. As follows from our analysis of asteroid spectral characteristics, reflectance spectra of some of asteroids obtained near perihelion at good photometric conditions turned out to be very different in comparison with their spectra from SMASSII database and those of their probable meteorite analogs. We suggested that
presence of a scattering media, like a dust exosphere arising due to sublimation of subsurface deposits of water ice on primitive-type asteroids near perihelion (at the highest subsolar temperatures), might have been an obstacle for a correct determination of their chemical and mineral matter composition by the spectral method. At the same time, such phenomenon (if present) could be
used as an indication of a considerable H2O content in interiors of asteroids considered.