Dynamical relations between asteroids, meteorites and Apollo-Amor objects

A Monte-Carlo technique has been used to investigate the orbital evolution of asteroidal collision debris produced interior to 2.6 AU. It is found that there are two regions primarily responsible for production of Earth-crossing meteoritic material and Apollo objects. The region adjacent to the 3:1 jovian commensurability resonance (2.5 AU) is unique in providing material in the required quantity and orbital distribution of the ordinary chondrites. This region should also supply a comparable preatmospheric flux of carbonaceous meteorites. The innermost asteroid belt (2.17-2.25 AU), via the v 6 secular resonance, provides a flux ca. 9% that of the ordinary chondrites, and appears to be the strongest candidate for the basaltic achondrite source region. It is unlikely that a significant number of meteorites originate beyond 2.6 AU. It is speculated that enstatite achondrites are derived from the Hungaria region, interior to the main belt, and that iron and stony-iron meteorites originate from many main-belt sources interior to 2.6 AU.

Laboratory investigations of meteorite luminescence

Apparatus has been constructed for the irradiation of mineral dust samples with protons and ultraviolet radiation. The spectrum of any resulting luminescence emission is scanned by a photoelectric grating spectrophotometer. A range of meteorites of different classes has been investigated; only the enstatite achondrites luminesce strongly. The enstatite constituent is responsible for the luminescence, but the emission may be predominantly red or blue; there is some evidence that the difference between these two conditions is one of manganese content. Several other classes of meteorite luminesce weakly; some spectra are given, showing changes with proton damage.