Asteroid taxonomic classes

class mean albedo spectral reflectivity (at wavelengths of 0.3–1.1 micrometres 【μm】)

C 0.05 neutral, slight absorption at wavelengths of 0.4 μm or shorter

D 0.04 very red at wavelengths of 0.7 μm or longer

F 0.05 flat

P 0.04 featureless, sloping up into red*

G 0.09 similar to C class but with a deeper absorption at wavelengths of 0.4 μm or shorter

K 0.12 similar to S class but with lower slopes

T 0.08 moderately sloped with weak ultraviolet and infrared absorption bands

B 0.14 similar to C class but with shallower slope toward longer wavelengths

M 0.14 featureless, sloping up into red*

Q 0.21 strong absorption features shortward and longward of 0.7 μm

S 0.18 very red at wavelengths of less than 0.7 μm, typically with an absorption band between 0.9 and 1.0 μm

A 0.42 extremely red at wavelengths shorter than 0.7 μm and a deep absorption longward of 0.7 μm

E 0.44 featureless, sloping up into red*

R 0.35 similar to A class but with slightly weaker absorption bands

V 0.34 very red at wavelengths of less than 0.7 μm and a deep absorption band centred near 0.95 μm

other any any object not falling into one of the above classes

*Classes E, M, and P are spectrally indistinguishable at these wavelengths and require an independent albedo measurement for unambiguous classification.