The impact of the dust size-distribution on the angular momentum in star formation

Dust grains play a major role during the protostellar collapse. Through their ionization and coagulation, they alter the coupling between the gas and the magnetic field, leading to a modified transport of angular momentum by magnetic braking. Emulating the coagulation process, by removing the small grains from the size-distribution while keeping the same dust-to-gas ratio, enhances the ambipolar diffusion, hence weakening the magnetic braking. We find that this removal allows for more angular momentum to stay into the circumstellar disk, while significantly weakening the outflow. In this case, we also observe, for the first time, an ionic precursor to the outflow with velocities of several km s^-1 against the collapse of the gas.