  Recent work has shown that aside from the classical view of collisions by
increasingly massive planetesimals, the accretion of mm- to m-sized 'pebbles'
can also reproduce the mass-orbit distribution of the terrestrial planets.
Here, we perform N-body simulations to study the effects of pebble accretion
onto growing planetesimals of different diameters located in the inner Solar
System. The simulations are run to occur during the lifetime of the gas disc
while also simultaneously taking Jupiter's growth into account. We find that
pebble accretion can increase the mass in the solid disc by at least a few
times its initial mass with reasonable assumptions that pebbles fragment to
smaller-sized grains at the snow line and that gas-disc-induced orbital
migration effects are in force. Such a large contribution in mass by pebbles
would seem to imply that the isotopic composition of the inner Solar System
should be similar to the pebble source (i.e. outer Solar System). This
implication appears to violate the observed nucleosynthetic isotopic dichotomy
of the sampled Solar System. Thus, pebble accretion played little or no role in
terrestrial planet formation.
