Context. Based on the viscous disk theory, a number of recent studies have suggested there is large-scale meridional circulation in protoplanetary disks. Such a flow could account for the presence of crystalline silicates, including calcium- and alumi . . .

Exoplanets are often associated with disks of dust and debris, analogs of the Kuiper Belt in our solar system. These "debris disks" show a variety of non-trivial structures attributed to planetary perturbations and utilized to constrain the properties . . .

Large scale anticyclonic vortices concentrate solid material in disks and may thus behave as a route for fast planet formation. The debate over their 3D stability in recent years has lead to the conclusion that they are stable to 3D perturbations prov . . .

Radial magnetic fields that resist orbital shear can explain the outwards angular momentum transport required for accretion in non-self-gravitating disks. This generates azimuthal magnetic fields and thus Maxwell stresses that transfer angular momentu . . .

Galactic nuclei should contain a cluster of stars and compact objects in the vicinity of the central supermassive black hole due to stellar evolution, minor mergers and gravitational dynamical friction. By analogy with protoplanetary migration, nuclea . . .

Aims. We present global 3D MHD simulations of disks of gas and solids, aiming at developing models that can be used to study various scenarios of planet formation and planet-disk interaction in turbulent accretion disks. A second goal is to demonstrat . . .

If intermediate-mass black holes (IMBHs) grow efficiently in gas discs around supermassive black holes, their host active galactic nucleus (AGN) discs should exhibit myriad observational signatures. Gap-opening IMBHs in AGN discs can exhibit spectral . . .

Recent years have shown that accretion disks around young stars have extended regions, which are too low ionized to couple to magnetic fields and thus the nature of the underlying turbulence cannot be exclusively magnetic. We also found that disks hav . . .

The Protoplanetary Discussions conference - held in Edinburgh, UK, from 7th-11th March 2016 - included several open sessions led by participants. This paper reports on the discussions collectively concerned with the multiphysics modelling of protoplan . . .

The fact that most extrasolar planets found to date are orbiting metal-rich stars lends credence to the core accretion mechanism of gas giant planet formation over its competitor, the disc instability mechanism. However, the core accretion mechanism i . . .