Accretion of 1/10 M_⊕ by a core of 5 M_⊕: envelope mass (top) and envelope accretion rate (bottom). Nominal case (constant Ṁ_z, dashed line) vs. sudden accretion of 1/10 M_⊕ (solid line) vs. shut-off of core luminosity (dotted line). The timescale for impact and shut-off is 0.01 Myr. The offset of impact to shut-off comes from the fact that the core luminosity first rises and then decreases causing a delay. Also the mathematical prescription for core-luminosity differs slightly for shut-off and impact. In this case the shut-off case is more massive at the end. This is not so for larger impacts because the larger core mass post impact leads to larger accretion rates and eventually larger envelope mass. Note that the peak accretion rate is larger after the impact than after the shut-off.