Gas accretion compared to shutdown scenario. Black lines show the envelope mass after 1 M_⊕ impacts on cores of 8–12 M_⊕. Red lines show the evolution when the core accretion rate is simply shut off with the same timescale and to the same background rate instead of impacting 1 M_⊕. Dashed lines show the envelope mass of the NC for the largest and smallest target. At 1 Myr the NC and the impact case have the same core size. Cases 8–11 have been extended beyond the 1 Myr t_comp that was usually adopted to compare to the NC.