  When a planet becomes massive enough, it gradually carves a partial gap
around its orbit in the protoplanetary disk. A pressure maximum can be formed
outside the gap where solids that are loosely coupled to the gas, typically in
the pebble size range, can be trapped. The minimum planet mass for building
such a trap, which is called the pebble isolation mass (PIM), is important for
two reasons: it marks the end of planetary growth by pebble accretion, and the
trapped dust forms a ring that may be observed with millimetre observations. We
study the effect of disk turbulence on the pebble isolation mass and find its
dependence on the gas turbulent viscosity, aspect ratio, and particles Stokes
number. By means of 2D gas hydrodynamical simulations, we found the minimum
planet mass to form a radial pressure maximum beyond the orbit of the planet,
which is the necessary condition to trap pebbles. We then carried out 2D gas
plus dust hydrodynamical simulations to examine how dust turbulent diffusion
impacts particles trapping at the pressure maximum. We finally provide a
semi-analytical calculation of the PIM based on comparing the radial drift
velocity of solids and the root mean square turbulent velocity fluctuations
around the pressure maximum. From our results of gas simulations, we provide an
expression for the PIM versus disk aspect ratio and turbulent viscosity. Our
gas plus dust simulations show that the effective PIM can be nearly an order of
magnitude larger in high-viscosity disks because turbulence diffuse particles
out of the pressure maximum. This is quantified by our semi-analytical
calculation, which gives an explicit dependence of the PIM with Stokes number
of particles. We conclude than disk turbulence can significantly alter the PIM,
depending on the level of turbulence in regions of planet formation.
