in the primitive CR3 chondrites QUE 99177 and MET 00426.
Floss C. and Stadermann F. J. (2009)
Lunar & Planet. Sci. 40, Abstract #1083.
Presolar material incorporated into primitive solar system
bodies consists of both circumstellar stardust formed in the outflows
of RG or AGB stars and the ejecta of supernovae, and interstellar
material thought to form via low temperature ion-molecule reactions in
cold molecular clouds. Deuterium and N isotopic anomalies associated
with the latter are common in interplanetary dust particles (IDPs) and
in various primitive meteorites, notably the CR chondrites. Carbon
isotopic anomalies are less common, but have also been observed. QUE
99177 and MET 00426 are CR3 chondrites that have experienced little
aqueous alteration compared to other members of this meteorite group.
The carbonaceous matter in these meteorites exhibits a low degree of
crystallinity and contains detectable amounts of N, indicating that
this material has not experienced significant thermal processing. Both
also contain high abundances of O-anomalous and C-anomalous grains,
consistent with their primitive natures. Here we report on the N
isotopic distributions of these two meteorites.