asteroidtype

Asteroid type refers to the classification of asteroids based on their spectral reflectance, albedo, and inferred composition. The most common classification system, developed from observations of the asteroid belt in the early 1990s, groups asteroids into three principal spectral classes: C-type, S-type, and M-type, with numerous subtypes and other families such as B, D, P, and V.

C-type asteroids are carbonaceous and constitute about 75% of the main-belt population. They exhibit low albedos and featureless spectra with a pronounced ultraviolet drop, indicating a high proportion of water‑ice, carbon compounds, and silicates. They are thought to be remnants of the early solar nebula and are often found in the outer belt.

S-type asteroids are relatively bright (higher albedo) and make up roughly 17% of belt objects. Their spectra show absorption features around 1 and 2 microns, pointing to silicate minerals such as olivine and pyroxene. S-types dominate the inner belt and are linked to ordinary chondrite meteorites that impact Earth.

M-type asteroids, identified by moderate albedo and relatively featureless spectra, comprise around 3% of the belt. They are believed to be metallic or differentiated, possibly remnants of planetary cores. The scarcity of M-types and their distribution suggests that planetary differentiation and collisional evolution play a significant role in the belt's history.

Other minor classes, such as D- and P-types, are characterized by very low albedo and featureless red‑sloped spectra, often found farther from the Sun and associated with cometary materials. V-types, or basaltic asteroids, are linked to differentiated bodies like Vesta and exhibit a distinct absorption band near 1 micron.

Asteroid taxonomy is continually refined as new spectroscopic and radar data become available, enhancing our understanding of planetary formation and the distribution of materials in the early solar system.