On the growth efficiency of pebble-accreting planetesimals at 1 AU orbital distance from the star

Abstract

One method to build planets is through pebble accretion, where a planetesimal sweeps up pebbles in the protoplanetary disk surrounding the star. I investigated the growth efficiency of planetesimals by numerically integrating the equation of motion for variable sized pebbles. These pebbles experience gas drag and interact gravitationally with the planetesimal and the star. The results are obtained by quantifying accretion in terms of a growth timescale. I obtained a finite transition between the flow-dominated regime \cite{guillot} and the settling regime \cite{Ormel}. A barrier is preventing growth of planetesimals sweeping up particles smaller than 1 centimeter.