Close-in super-Earths, with radii R≈ 2–5 R⊕ and orbital periods P< 100 d, orbit more than
half, and perhaps nearly all, Sun-like stars in the Universe. We use this omnipresent …

Accumulation of dust and ice particles into planetesimals is an important step in the planet
formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores …

The size distribution of asteroids and Kuiper belt objects in the solar system is difficult to
reconcile with a bottom-up formation scenario due to the observed scarcity of objects smaller …

We present Phantom, a fast, parallel, modular, and low-memory smoothed particle
hydrodynamics and magnetohydrodynamics code developed over the last decade for …

We present local two-dimensional and three-dimensional hybrid numerical simulations of
particles and gas in the midplane of protoplanetary disks (PPDs) using the Athena code. The …

Planets appear to form in environments shaped by the gas flowing through protostellar disks
to the central young stars. The flows in turn are governed by orbital angular momentum …

The vertical shear instability (VSI) offers a potential hydrodynamic mechanism for angular
momentum transport in protoplanetary disks (PPDs). The VSI is driven by a weak vertical …

There is considerable interest in hydrodynamic instabilities in dead zones of protoplanetary
disks as a mechanism for driving angular momentum transport and as a source of particle …

We study the gravitational instability (GI) of small solids in a gas disk as a mechanism to form
planetesimals. Dissipation from gas drag introduces secular GI, which proceeds even when …

Enhancing the local dust-to-gas ratio in protoplanetary discs is a necessary first step to
planetesimal formation. In laminar discs, dust settling is an efficient mechanism to raise the …