Related papers: Accretion bursts in magnetized gas-dust protoplane…
We have investigated evolution of magneto-rotational instability (MRI) in protoplanetary disks that have radially non-uniform magnetic field such that stable and unstable regions coexist initially, and found that a zone in which the disk…
We investigate the formation and early evolution of a protostellar disc from a magnetized pre-stellar core using non-ideal magnetohydrodynamic (MHD) simulations including ambipolar diffusion and Ohmic dissipation. The dynamical contraction…
We revisit our original papers on the burst mode of accretion by incorporating a detailed energy balance equation into a thin-disk model for the formation and evolution of circumstellar disks around low-mass protostars.Our model includes…
We investigate the conditions for the presence of a magnetically inactive dead zone in protostellar disks, using 3-D shearing-box MHD calculations including vertical stratification, Ohmic resistivity and time-dependent ionization chemistry.…
We investigate the effects of different dust and gas opacity descriptions on the structure and evolution of the inner regions of protoplanetary discs. The influence on the episodic instability of the inner rim is hereby of central interest.…
We characterize magnetically driven accretion at radii between 1 au and 100 au in protoplanetary discs, using a series of local non-ideal magnetohydrodynamic (MHD) simulations. The simulations assume a Minimum Mass Solar Nebula (MMSN) disc…
The early evolution of protostellar, star-forming discs, including their density structure, turbulence, magnetic dynamics, and accretion variability, remains poorly understood. We present high-resolution magnetohydrodynamic simulations,…
We examine the small-scale dynamics of black hole accretion disks in which radiation pressure exceeds gas pressure. Local patches of disk are modeled by numerically integrating the equations of radiation MHD in the flux-limited diffusion…
The irradiation of protoplanetary discs by central stars is the main heating mechanism for discs, resulting in their flared geometric structure. In a series of papers, we investigate the deep links between 2D self-consistent disc structure…
A physical mechanism that drives FU Orionis-type outbursts is reconsidered. We study the effect of inner part of a circumstellar disk covering a region from near the central star to the radius of approximately $5$ AU (hereafter, the inner…
In protoplanetary disks, the inner radial boundary between the MRI turbulent (`active') and MRI quiescent (`dead') zones plays an important role in models of the disk evolution and in some planet formation scenarios. In reality, this…
Protostellar accretion discs have cool, dense midplanes where externally originating ionisation sources such as X-rays or cosmic rays are unable to penetrate. This suggests that for a wide range of radii, MHD turbulence can only be…
Aims. Accretion and luminosity bursts triggered by three distinct mechanisms: the magnetorotational instability in the inner disk regions, clump infall in gravitationally fragmented disks and close encounters with an intruder star, were…
Magnetohydrodynamic accretion disk simulations suggest that much of the energy liberated by the magnetorotational instability (MRI) can be channeled into large-scale toroidal magnetic fields through dynamo action. Under certain conditions,…
In the early stages of star formation, boundary layer accretion, where protostars accrete material from disks extending down to their surfaces, plays a crucial role. Understanding how a magneto-rotational-instability (MRI)-active disk…
We address two outstanding issues in the sequential accretion scenario for gas giant planet formation, the retention of dust grains in the presence of gas drag and that of cores despite type I migration. The efficiency of these processes is…
Most protoplanetary discs are thought to undergo violent and frequent accretion outbursts, during which the accretion rate and central luminosity are elevated for several decades. This temporarily increases the disc temperature, leading to…
Discs of gas and dust are ubiquitous around protostars. Hypothetical disc viscosity is thought to cause the gas and dust to accrete onto the star. Turbulence within the disc might be the source of this disc viscosity. However, observed…
Like their lower mass siblings, massive protostars can be expected to: a) be surrounded by circumstellar disks and b) launch magnetically-driven jets and outflows. The disk formation and global evolution is thereby controlled by advection…
We perform global time-dependent simulations of an accretion disc around a young stellar object with a dead zone (a region where the magneto-rotational instability cannot drive turbulence because the material is not sufficiently ionised).…