We present the first 3.8 µm image of the dusty ring surrounding the young binary system GG Tau, obtained with the W. M. Keck II 10 m telescope's adap-tive optics system. This is the longest wavelength at which the ring has been detected in scattered light so far, allowing a multi-wavelength analysis of the scattering properties of the dust grains present in this protoplanetary disk in combinati...

Elongated dust grains exist in astrophysical plasmas. Anisotropic growth of elliptical dust grains, via plasma deposition, occurs if the deposited ions are non-inertial. In reality the extent of such growth depends upon the initial kinetic energy of the ions and the magnitude of the electric field in the sheath. Simulations of the dynamics of the ions in the sheath are reported, showing how ell...

We perform numerical simulations of the Kelvin-Helmholtz instability in the mid-plane of a protoplanetary disc. A two-dimensional corotating slice in the azimuthal–vertical plane of the disc is considered where we include the Coriolis force and the radial advection of the Keplerian rotation flow. Dust grains, treated as individual particles, move under the influence of friction with the gas, wh...

We consider the generalized Störmer Problem that includes the electromagnetic and gravitational forces on a charged dust grain near a planet. For dust grains a typical charge to mass ratio is such that neither force can be neglected. Including the gravitational force gives rise to stable circular orbits that encircle that plane entirely above/below the equatorial plane. The effects of the diffe...

We present the mass distribution of interstellar grains measured in situ by the Galileo and Ulysses spaceprobes as cumulative flux. The derived in situ mass distribution per logarithmic size interval is compared to the distribution determined by fitting extinction measurements. Large grains measured in situ contribute significantly to the overall mass of dust in the local interstellar cloud. Th...

We introduce a dust model for cosmological simulations implemented in the movingmesh code arepo and present a suite of cosmological hydrodynamical zoom-in simulations to study dust formation within galactic haloes. Our model accounts for the stellar production of dust, accretion of gas-phase metals onto existing grains, destruction of dust through local supernova activity, and dust driven by wi...

We discuss a new type of dust acceleration mechanism that acts in a turbulent magnetized medium. The magnetohydrodynamic (MHD) turbulence can accelerate grains through resonant as well as nonresonant interactions. We show that the magnetic compression provides higher velocities for super-Alfvénic turbulence and can accelerate an extended range of grains in warm media compared to gyroresonance. ...