Topic summary
Tholen classification
Extracted from the Wikipedia article Asteroid spectral types.
Tholen classification
The most widely used taxonomy is that of David J. Tholen, first proposed in 1984. This classification was developed from broad band spectra (between 0.31 μm and 1.06 μm) obtained during the Eight-Color Asteroid Survey (ECAS) in the 1980s, in combination with albedo measurements. The original formulation was based on 978 asteroids. The Tholen scheme includes 14 types with the majority of asteroids falling into one of three broad categories, and several smaller types (also see § Overview of Tholen and SMASS above). The types are, with their largest exemplars in parentheses: