Figure 5

From top left to bottom right : Surface density, temperature, \(\pmb{\mbox{H}_{2}}\) fraction, and Toomre Q parameter in the Keplerian disk that forms around the central protostar. For \(Q\lesssim1\), the disk becomes gravitationally unstable and fragments. In this simulation, the first fragment forms after \({\simeq}90\mbox { yr}\) at a distance of \({\simeq}20\mbox { au}\) from the central protostar. Adapted from Clark et al. (2011b).