asteroid spectral types – David Darling, What are C Type S type and M type asteroids?, asteroid spectral types – David Darling, asteroid spectral types – David Darling, S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition , hence the name. Approximately 17% of asteroids are of this type, making it the second most common after the carbonaceous C-type .
S-type asteroid. A moderately bright, slightly reddish type of asteroid believed to be composed largely of silicate minerals (the S stands for siliceous) such as olivine and pyroxene.
S-type asteroids , with an astronomical albedo of typically 0.20, are moderately bright and consist mainly of iron- and magnesium-silicates. They are dominant in the inner part of the asteroid belt within 2.2 AU, common in the central belt within about 3 AU, but become rare farther out.
S-type (silicate-rich) asteroids are more common toward the inner region of the belt, within 2.5 AU of the Sun. The spectra of their surfaces reveal the presence of silicates and some metal, but no significant carbonaceous compounds. This indicates that their materials have been significantly modified from their primordial composition, probably through melting and reformation.
