The rare
O-type asteroids have spectra similar to the unusual asteroid
3628 Boznemcová, which is the best
asteroid match to the spectra of L6 and LL6 ordinary
chondrite meteorites. Their spectra have a deep absorption feature longward of 0.75 μm.
References
S. J. Bus and R. P. Binzel Phase II of the Small Main-belt Asteroid Spectroscopy Survey: A feature-based taxonomy, Icarus, Vol. 158, pp. 146 (2002).