  Stardust grains that originated in ancient stars and supernovae are recovered
from meteorites and carry the detailed composition of their astronomical sites
of origin. We present evidence that the majority of large ($\mu$m-sized)
meteoritic silicon carbide (SiC) grains formed in C-rich asymptotic giant
branch (AGB) stars that were more metal-rich than the Sun. In the framework of
the slow neutron-captures (the s process) that occurs in AGB stars the
lower-than-solar 88Sr/86Sr isotopic ratios measured in the large SiC grains can
only be accompanied by Ce/Y elemental ratios that are also lower than solar,
and predominately observed in metal-rich barium stars - the binary companions
of AGB stars. Such an origin suggests that these large grains represent the
material from high-metallicity AGB stars needed to explain the s-process
nucleosynthesis variations observed in bulk meteorites (Ek et al. 2020). In the
outflows of metal-rich, C-rich AGB stars SiC grains are predicted to be small
($\simeq$ 0.2 $\mu$m-sized); large ($\simeq$ $\mu$m-sized) SiC grains can grow
if the number of dust seeds is two to three orders of magnitude lower than the
standard value of $10^{-13}$ times the number of H atoms. We therefore predict
that with increasing metallicity the number of dust seeds might decrease,
resulting in the production of larger SiC grains.
