Isotopic anomalies are departures from the laws of mass-dependent fractionation that cannot be explained by radioactive decay, cosmogenic effects, or exotic isotopic fractionation processes such as nuclear field shift or magnetic effects [1 and references therein]. These anomalies often have a nucleosynthetic origin and provide clues on the stellar origin and solar system processing of presolar dust. Anomalies are most often found in refractory elements of relatively low mass, so Sr is a prime target for study. The four stable isotopes of strontium are useful for discerning the various nucleosynthetic origins of early
solar system building blocks and the timing of
accretion processes. Strontium-84 is the least abundant
(0.56%) of these isotopes, but is particularly significant
in being a p-process only nuclide that is produced in
core-collapse or type Ia supernovae [2,3]. The more
abundant isotopes ^(86)Sr (9.86%), ^(87)Sr (7.00%) and ^(88)Sr (82.58%) are produced in s- and r-processes in
asymptotic giant branch stars and other stellar types
[4]. Additionally, ^(87)Sr is produced by ^(87)Rb decay in
proportions that dominate over possible nucleosynthetic variations but provide timings of early solar system processes, most notably volatile element depletion [5-7]. Furthermore, variations in strontium isotopic ratios caused by high-temperature massdependent fractionation [8] are also important [9-12], as they provide insights into nebular and accretionary processes
