Recent developments in the study of presolar grains

Abstract

Studies of presolar grains have provided a wealth of data that are relevant to astrophysics. Their isotopic ratios are especially informative for understanding stellar nucleosynthesis and mixing in stars and stellar ejecta. In the past few years, isotopic ratios of heavy elements in single presolar grains have been analyzed with resonant ionization mass spectrometry. Molybdenum, Zr, and Ba isotopic patterns of SiC grains of a supernova origin agree with patterns predicted for a neutron burst. A new type of ion microprobe, the NanoSIMS, with its high sensitivity and small beam diameter, makes isotopic analyses of submicron grains possible.