Protostellar mass accretion rates from gravoturbulent fragmentation

We analyse protostellar mass accretion rates u M from numerical models of star formation based on gravoturbulent fragmentation, considering a large number of different environments. To within one order of magnitude, u M ≈ MJ/τff with MJ being the mean thermal Jeans mass and τff the corresponding free-fall time. However, mass accretion rates are highly time- variant, with a sharp peak shortly after the formation of the protostellar core. We present an empirical exponential fit formula to describe the time evolution of the mass accretion and discuss the resulting fit parameters. There is a positive correlation between the peak accretion rate and the final mass of the protostar. We also investigate the relation of u M with the turbulent flow velocity as well as with the driving wavenumbers in different environments. We then compare our results with other theoretical models of star formation and with observational data.