  We develop a simple model of planetary formation, focusing our attention on
those planets with masses less than 10 Earth masses and studying particularly
the primordial spin parameters of planets resulting from the accretion of
planetesimals and produced by the collisions between the embryos. As initial
conditions, we adopt the oligarchic growth regime of protoplanets in a disc
where several embryos are allowed to form. We take different initial planetary
system parameters and for each initial condition, we consider an evolution of
20 millon of years of the system. We perform simulations for 1000 different
discs, and from their results we derive the statistical properties of the
assembled planets. We have taken special attention to the planetary obliquities
and rotation periods, such as the information obtained from the mass and semi
major axis diagram, which reflects the process of planetary formation. The
distribution of obliquities was found to be isotropic, which means that planets
can rotate in direct or indirect sense, regardless of their mass. Our results
regarding the primordial rotation periods show that they are dependent on the
region where the embryo was formed and evolved. According to our results, most
of the planets have rotation periods between 10 and 10000 hours and there are
also a large population of planets similar to terrestrial planets in the Solar
System.
