The evolution of the protoplanetary disk with mass influx from a molecular cloud core and the photoevaporation winds

Abstract

We investigate the formation, evolution, and dispersal processes of protoplanetary disks with mass influx from the gravitational collapse of a molecular cloud core and the photoevaporation winds. Due to the initial angular momentum of the molecular cloud core, the gravitational collapse of the molecular cloud core forms a protostar+protoplanetary disk system. We calculate the evolution of the protoplanetary disk from the gravitational collapse of the molecular cloud core to the dispersal stage. In our calculation, we include the mass influx from a molecular cloud core, the irradiation from the central star, the viscosity due to the magnetohydrodynamic (MHD) turbulence driven by the magnetorotational instability (MRI) and the gravitational instability, and the effect of photoevaporation. We find that the protoplanetary disk has some interesting properties, which are different from the previous studies. Firstly, with particular values of parameters of the molecular cloud core, the gravitational instability does not occur during the whole evolution of the resultant protoplanetary disk. With some other parameters of the molecular cloud core, the gravitational instability occurs all the time of the lifetime of the resultant protoplanetary disk. Secondly, the radial distribution of the α parameter exhibits a nearly ladder-like shape, which is different from the three regions’ shape in previous studies. Thirdly, the value of the surface density is increased significantly (about a factor of 8.0) compared with that in the Minimum Mass Solar Nebula (MMSN) model. We suggest that this increased surface density can provide enough material for the formation of giant planets within the lifetime of the protoplanetary disk, and may provide a routine for reducing the timescale of the formation of giant planets. We also discuss the influence of the photoevaporation winds on the evolution of the protoplanetary disk.