  The relative chemical abundances between CI meteorites and the solar
photosphere exhibit a significant trend with condensation temperature. A trend
with condensation temperature is also seen when the solar photospheric
abundances are compared to those of nearby solar twins. We use both these
trends to determine the alteration of the elemental abundances of the
meteorties and the photosphere by fractionation and calculate a new set of
primordial Solar System abundances.
