Forbidden lines of atomic oxygen at 6300 and 5577 Angstroms and rovibrational lines of CO near 4.7 microns are relatively strong and well-observed in T Tauri stars. The oxygen lines have been touted as the ``smoking gun" of photoevaporative winds, but after considering the requirements for their excitation, we conclude that they are at least as likely to form in magnetothermal winds such as...
Many planets orbit within an AU of their stars, raising questions about their origins. Particularly puzzling are the planets found near the silicate sublimation front. We investigate conditions near the front in the protostellar disk around a young intermediate-mass star, using the first global 3-D radiation non-ideal MHD simulations in this context.
The results show magnetorotational...
Observations point toward weak levels of turbulence in protoplanetary disks, and theoretical studies now focus on magneto-thermal winds rather than MRI turbulence as the main driver of mass accretion. Although MHD turbulence might be quenched, laminar magnetic structures may still transport angular momentum and induce substantial accretion heating inside the disk. Using steady-state radiative...
Both the Core Accretion and the Gravitational Instability models for giant planet formation predict the presence of circumplanetary discs (CPDs) during the last formation phases (Alibert et al. 2005, Ward & Canup 2010). These discs are found to be continuously fed by an influx of gas from the protoplanetary disc (Tanigawa et al. 2012). Magnetic fields generated by the disc itself could play a...
Recent observations have found shorter lifetimes of protoplanetary disks (PPDs) in low-metallicity environments than in the solar neighborhood (Yasui et al. 2009, 2010). It suggests a more efficient disk dispersal with decreasing metallicity. Prior studies have shown that photoevaporation is one of the essential disk-dispersing mechanisms that can yield sufficient mass-loss rates consistent...
Photoevaporation and magnetically driven winds are two independent mechanisms that remove mass from protoplanetary disks. In addition to accretion, the effect of these two principles acting concurrently could be significant, and the transition between them has not yet been extensively studied and quantified.
In order to contribute to the understanding of disk winds, we present the phenomena...
Laminar outflows driven by large-scale magnetic fields likely play an important role in the evolution and dispersal of protoplanetary disks, and in setting the conditions for planet formation. Extending our previous non-ideal MHD model with radiative transfer as well as a simplified thermochemistry, we follow the dual aim of studying the influence of thermal driving and, at the same time,...
Transition discs provide an important tool to probe various mechanisms that might influence the evolution of protoplanetary discs and therefore the formation of planetary systems. One of these mechanisms is photoevaporation due to energetic radiation from the central star, which can in principal explain the occurrence of discs with inner cavities. Current models, however, fail to reproduce a...
Thermal processes can play an important role in dynamics, chemistry, and dust growth of protoplanetary disks. Using numerical hydrodynamics simulations in the thin-disk limit, we explore different approaches to computing the disk thermal structure: a simplified beta-cooling approach, in which the rate of disk cooling is proportional to the local dynamical time, a fiducial model with equal...
