To study the terrestrial-type planet formation during the post oligarchic
growth, the initial distributions of planetary embryos and planetesimals used
in N-body simulations play an important role. Most of these studies typically
use ad hoc initial distributions based on theoretical and numerical studies. We
analyze the formation of planetary systems without gas giants around solar-type
stars focusing on the sensitivity of the results to the particular initial
distributions of planetesimals and embryos. The formation of terrestrial
planets in the habitable zone (HZ) and their final water contents are topics of
interest. We developed two different sets of N-body simulations from the same
protoplanetary disk. The first set assumes ad hoc initial distributions for
embryos and planetesimals and the second set obtains these distributions from
the results of a semi-analytical model which simulates the evolution of the
gaseous phase of the disk. Both sets form planets in the HZ. Ad hoc initial
conditions form planets in the HZ with masses from 0.66M⊕ to
2.27M⊕. More realistic initial conditions obtained from a
semi-analytical model, form planets with masses between 1.18M⊕ and
2.21M⊕. Both sets form planets in the HZ with water contents between
4.5% and 39.48% by mass. Those planets with the highest water contents respect
to those with the lowest, present differences regarding the sources of water
supply. We suggest that the number of planets in the HZ is not sensitive to the
particular initial distribution of embryos and planetesimals and thus, the
results are globally similar between both sets. However, the main differences
are associated to the accretion history of the planets in the HZ. These
discrepancies have a direct impact in the accretion of water-rich material and
in the physical characteristics of the resulting planets.Comment: Accepted for publication in Astronomy and Astrophysics, 13 pages, 9
figure