The Formation of Brown Dwarfs

Abstract

Numerous brown dwarfs have been found in recent years, re-igniting debate about their origin. A natural way to stunt the growth of a nascent stellar embryo is to eject it out of the infalling gas envelope. This can be achieved by dynamical interactions in newborn multiple systems or small-N clusters of stellar embryos. In this scenario brown dwarfs form like stars, but are sent into distant orbits or completely ejected, thus depriving them of sufficient growth to ever exceed the hydrogen burning limit of 0.08 M_⊙. Decay of a multiple system is a stochastic process and, with better luck, brown dwarfs could indeed have become normal stars.