From streamers to stars: Overcoming mass loss in protoplanetary disks
Year: 2026
Type: article
Abstract: Recent high-resolution observations have revealed filamentary accretion flows (streamers) in protoplanetary disks older than 1 Myr, suggesting that late-stage interstellar gas infall (late infall) might affect disk evolution and stellar accretion. In Lupus, observations report a positive correlation between ambient gas density and stellar accretion rate. However, it remains unclear whether infall can truly boost stellar accretion, because incoming gas might instead be lost through photoevaporation or magnetically driven disk winds; alternatively, it could remain trapped in the outer disk. In this work, we performed 1D long-term (∼1--10 Myr) disk evolution simulations. We first treated late infall as a mass source and then included the effective torque arising from the angular-momentum difference between the infalling gas and Keplerian disk gas. We find that even if substantial gas reaches the outer disk (∼ 10^ 2 au), much of it is eventually lost through photoevaporation. Sustained stellar accretion therefore requires efficient inward gas delivery by mechanisms that locally remove angular momentum. Without an effective infall torque, strong viscosity can provide this transport, but it also ends up driving outward angular-momentum transport and excessive disk spreading, which is inconsistent with the compact disk sizes observed in Lupus. In contrast, magnetohydrodynamic (MHD) disk winds can remove angular momentum without significantly expanding the disk, allowing late infall to sustain stellar accretion, while keeping disks compact. Thus, if the Lupus accretion-density correlation is indeed caused by late infall without an effective infall torque, efficient angular-momentum removal by MHD disk winds would be required. In contrast, when the effective torque is included, the angular-momentum mismatch itself can promote inward gas transport and enhance stellar accretion, even without strong MHD disk winds.
Source: Astronomy and Astrophysics
Authors: W. Ooyama, R. Nakatani, T. Hosokawa, H. Mitani
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7162512334