Accreted gas mass as a function of time for a 5 M_⊕ core orbiting at 60 AU using the same disc model as Piso & Youdin (2014). We also show a reproduction of their model. When taking into account a more complex opacity model based on Bell & Lin (1994), resulting in lower opacity due to ice and silicate dust sublimation, gas accretion is slightly more efficient due to the increased luminosities. We also show the case when the surface terms in Eq. (11) are ignored which results in slightly slower gas accretion.