A class of asteroid, relatively common in the inner main asteroid belt, having a moderate albedo (0.10–0.28), a reddish spectrum at wavelengths shorter than 0.7 μm, and moderate to non-existent absorption features at longer wavelengths. The proportion of S-class asteroids decreases outwards through the main belt. The S is for silicaceous, since their composition is thought to include silicate minerals such as olivine and pyroxene. They could be the parent bodies of the stony-iron meteorites. Members of this class include (15) Eunomia, diameter 255 km, and (29) Amphitrite, diameter 212 km.
Subjects: Astronomy and Astrophysics.