It is suspected that they are not representative of typical
asteroid parent bodies, but rather of a select few which are advantageously placed to send impact fragments to Earth-crossing orbits. Such positions are e.g. near
Kirkwood gaps and/or
secular resonances in the
main asteroid belt. In fact, only the one rather insignificant asteroid
3628 Božněmcová has been identified to have a spectrum close to the ordinary chondrites. A probable parent body of the
H chondrites (comprising about 46% of the ordinary chondrites) is
6 Hebe, but its spectrum is dissimilar due to what is likely a metal impact melt component. It is likely that the ordinary chondrites comprise a detailed sample of but a few select asteroids which happen to have been in the right place at the right time to send many fragments toward Earth at the present moment in solar system history. On the other hand, observations of
243 Ida by the Galileo spacecraft found weathering of Ida's surface, and the reflection spectra of freshly exposed parts of the surface resembled that of OC meteorites, while the older regions matched the spectra of common
S-type asteroids. ==Chemical composition==