  Most major planetary bodies in the solar system rotate in the same direction
as their orbital motion: their spin is prograde. Theoretical studies to explain
the direction as well as the magnitude of the spin vector have had mixed
success. When the accreting building blocks are $\sim$ km-size planetesimals --
as predicted by the classical model -- the accretion process is so symmetric
that it cancels out prograde with retrograde spin contributions, rendering the
net spin minute. For this reason, the currently-favored model for the origin of
planetary rotation is the giant impact model, in which a single collision
suffices to deliver a spin, which magnitude is close to the breakup rotation
rate. However, the giant impact model does not naturally explain the preference
for prograde spin. Similarly, an increasing number of spin-vector measurement
of asteroids also shows that the spin vector of large (primordial) asteroids is
not isotropic. Here, we re-assess the viability of smaller particles to bestow
planetary bodies with a net spin, focusing on the pebble accretion model in
which gas drag and gravity join forces to accrete small particles at a large
cross section. Similar to the classical calculation for planetesimals, we
integrate the pebble equation of motion and measure the angular momentum
transfer at impact. We consider a variety of disk conditions and pebble
properties and conduct our calculations in the limits of 2D (planar) and 3D
(homogeneous) pebble distributions. We find that in certain regions of the
parameter space the angular momentum transfer is significant, much larger than
with planetesimals and on par with or exceeding the current spin of planetary
bodies.
