accumulation of particles, ranging from centimeters up to meters in diameter, into planetesimals in a protoplanetary disk that is enhanced by aerodynamic drag from the gas present in the disk, planeeditekke etapp, kus sentimeetrite kuni meetrite suurused triivkivid akumuleeruvad planetesimaalideks ja mida võimendab protoplanetaarse ketta gaasi aerodünaamiline takistus
