Origin of xenon-124 and -126 in carbonaceous chondrites

The present composition of atmospheric xenon in carbonaceous chondrites and other meteorites is shown here to result from high-energy proton irradiation on a primitive composition, which gives rise to secondary neutron-capture effects. With this new theory, we calculate a primordial (p-process) composition line and a spallogenic (x-process) composition line for the light isotopes 124Xe and 126Xe. All experimental values essentially lie between these two lines on a three isotope plot. Under these circumstances, it is not necessary to invoke exotic solar system material to explain the xenon anomalies observed in the carbonaceous chondrites. (author)