SPECTROPHOTOMETRY OF ASTEROIDS: THE ASSESSMENT OF THE MATERIAL COMPOSITION OF PRIMITIVE ASTEROIDS NEAR PERIHELION

Abstract

Using a qualitative interpretation of the reflectance spectra of asteroids, one can indirectly judge the mineralogy of the surface matter of these bodies. The spectral absorption bands are wide enough for correct interpretation even at low resolution. Thus, it is possible to assess the taxonomic class, as well as the prevailing type of mineralogy (low-temperature or high-temperature). In
addition to the classical definition of the spectral type, one can use such a feature of the asteroid as the appearance of a temporary exosphere, which affects the shape of the reflectance spectrum. Recently, the number of events of registration of sublimation activity among primitive asteroids has been increasing. We have obtained and analyzed the reflectance spectra of
12 asteroids of the Main Belt, mainly of primitive type. The aim of the study was to study the influence of the temporal exosphere on the correct determination of the spectral type of the asteroid. If the influence of the exosphere is small, then the correct determination of the asteroid’s class was possible. It is concluded that the data on asteroids of an unknown taxonomic class during their perihelion passage may give an incorrect idea of the prevailing type of mineralogy.