Formation of close-in super-Earths in evolving protoplanetary disks via disk winds
Recent magnetohydrodynamical simulations revealed the presence of magnetically-driven disk winds, which would alter the disk profile and the type I migration in the close-in region. We perform N-body simulations of formation of close-in super-Earths from embryos in a disk evolving via magnetically-driven disk winds. We find that the type I migration can be significantly suppressed when the gas surface density is decreased and has a flatter profile in the close-in region due to disk winds. In this case, planets undergo late orbital instability during the gas depletion, leading to a non-resonant configuration. Several observed distributions of close-in super-Earths (e.g., period-ratio distribution) can be reproduced. In addition, we show that in some results of simulations, systems with a chain of resonant planets form. We then implement the gas accretion of a primitive atmosphere from a protoplanetary disk on N-body code. By performing N-body simulations, we find that super-Earths can avoid runaway gas accretion if the gas accretion rate is limited by rapid global gas flows near the disk surface.