Dispersal of protoplanetary discs by the combination of magnetically driven and photoevaporative winds

Abstract

We investigate the roles of magnetically driven disk wind (MDW) and thermally driven photoevaporative wind (PEW) in the long-time evolution of protoplanetary disks. We start simulations from the early phase in which the disk mass is 0.118 M around a 1 M star and track the evolution until the disk is completely dispersed. We incorporate the mass loss by PEW and the mass loss and magnetic braking (wind torque) by MDW, in addition to the viscous accretion, viscous heating, and stellar irradiation. We find that MDW and PEW respectively have different roles: magnetically driven wind ejects materials from an inner disk in the early phase, whereas photoevaporation has a dominant role in the late phase in the outer ( 1 au) disk. The disk lifetime, which depends on the combination of MDW, PEW, and viscous accretion, shows a large variation of ∼ 1-20 Myr; the gas is dispersed mainly by the MDW and the PEW in the cases with a low viscosity and the lifetime is sensitive to the mass-loss rate and torque of the MDW, whereas the lifetime is insensitive to these parameters when the viscosity is high. Even in disks with very weak turbulence, the cooperation of MDW and PEW enables the disk dispersal within a few Myr.

Boosting the public engagement with astronomy through arts

“…This implies that while the central pair has formed together, while Proxima is a later acquisition, most likely being accreted during a stellar flyby. The time of this flyby is unknown, but the probability that it might have happened early enough while the central binary still had multiple planetesimals is low, just because this is a short period -of up to a few tens of millions of years [25,29] -with respect to the billion year age of the two main stars in the system. Dynamic studies of the Alpha Cen system also favor different origin of its components [15].…”

Early Initiation of Inner Solar System Formation at Dead-Zone Inner Edge

“…We adopt the weak disk-wind model proposed by (Suzuki et al 2016; see also Kunitomo et al 2020;Taki et al 2021) as the gas disk model. We also implement the effect of a dead-zone in the gas disk.…”

Unified Simulations of Planetary Formation and Atmospheric Evolution: Effects of Pebble Accretion, Giant Impacts, and Stellar Irradiation on Super-Earth Formation

“…Although the stellar XUVinduced photoevaporation would result in heating the gas at the disk surface which drives mass loss from the disk (e.g. Kunitomo et al 2020), the photoevaporative effect on the disk is not taken into account in this paper. The effect of disk photoevaporation will be investigated in our next paper.…”

“…We expect that such late-stage atmospheric accretion may not occur when photo-evaporation clears the inner disk after disk dispersal (t > 5 Myr). We will discuss the effect of disk photoevaporation, e.g., the disk evolution model developed in Kunitomo et al (2020), on the atmospheric growth of close-in super-Earths in our next paper. Figure 2 summarizes the results of five simulation runs for each case with different pebble fluxes.…”