The K-type was proposed by J. F. Bell and colleagues in 1988 for bodies having a particularly shallow 1 μm absorption feature, and lacking the 2 μm absorption.
K-型是J. F. Bell和他的同事在1988年提出的，這些小行星在1 μm有淺層的吸收特徵，在2 μm欠缺吸收。