Stable isotope measurements of meteorites and cosmic dust grains

Abstract

Although it was well known that a high 13 C abundance was a common feature of the spectra of evolved stars, it took over 50 years to find evidence of carbonaceous instellar dust, which might have been ejected from such objects, in the Solar System. However, it is now established that dust probably produced in novae and red giants can be located in primitive meteorites and the latest state of knowledge in respect of such components is reviewed herein. Nitrogen isotopic measurements have been helpful in distinguishing another form of dust that is carbonaceous but does not have a distinctive 13 C abundance. Likewise they suggest a non-carbonaceous material (possibly a sulphide) present in the meteorite Bencubbin could be a relict of supernovae outbursts. None of the components seen in meteorites can be detected in deep-sea spheres or stratospheric grains to provide a link between interstellar matter and comets. Until now interstellar dust has been the realm of observing astronomers and theoretians; stable isotope measurements are responsible for recognizing a material which it should be possible to isolate and study in the laboratory.