Corotation torque damping factor as a function of the ratio between the eccentricity and the dimensionless half-width of the horseshoe region for m_p = 3  M_⊕, and deduced from hydrodynamical simulations (triangles). The solid line corresponds to the function that best fits the simulation results. The dashed line is the prescription of Hellary & Nelson (2012) and the dash-dotted line corresponds to the prescription of Cossou et al. (2013).