Can s-Process Nucleosnthesis Explain the Calcium Isotopic Anomalies in Meteorites?

From 1970s, the calcium isotopes of meteorites have been studied. Compare
with the terrestrial abundance, there exists some anomalies, including
48Ca, within these isotopes. With a neutron-rich Type Ia supernovae model,
the 48Ca and others neutron rich isotopic anomalies had be solved. On the
other hand, the pre-solar grains studies also indicated both calcium(42Ca, 43Ca,
44Ca) and titanium anomalies. Amari et al.2000 and Nittler et al.2008 succeed
to explain these anomalies through an asymptotic giant branch(AGB)
star model to some degree.
The 43Ca anomalies, which has been found in presolar grains and solved
by an AGB star model, was found in the calcium-aluminium inclusions(CAIs)
recently. The excess of 43Ca/44Ca, 46Ca/44Ca & 48Ca/44Ca in the CAIs were
found to be 0.29±0.16, 1.11±5.51, 4.48±0.29 respectively. For that
reason, an AGB model is suggested to explain the CAIs measurement results.
In such a model, different parameter, especially the main factor, neutron
density was tuned in the simulation. All of the simulation generated a consistent
result - less neutron-rich isotopes(42Ca, 43Ca) can be created through the
s-process. Even through this model create less 46Ca anomalies, a significant
excess of 46Ca can be seen after the strategy of normalize to solar abundance
which is often used to analyse isotopic abundance. Nevertheless, a short time
neutron exposure will leave 46Ca no effect. In another case, if the mixing
model is considered, the 13C neutron source AGB stars will be a good candidate
for this 46Ca anomalies.