Related papers: The steady-state flow pattern past gravitating bod…
The fundamental difference between accretion around black holes and neutron stars is the inner boundary condition, which affects the behavior of matter very close to the compact objects. This leads to formation of additional shocks and…
We outline a scenario which traces a direct path from freely-floating nebula particles to the first 10-100km-sized bodies in the terrestrial planet region, producing planetesimals which have properties matching those of primitive meteorite…
We analyse the size evolution of pebbles accreted into the gaseous envelope of a protoplanet growing in a protoplanetary disc, taking into account collisions driven by the relative sedimentation speed as well as the convective gas motion.…
Planets intermediate in size between the Earth and Neptune, and orbiting closer to their host stars than Mercury does the Sun, are the most common type of planet revealed by exoplanet surveys over the last quarter century. Results from…
Any gravitating mass traversing a relatively sparse gas experiences a retarding force created by its disturbance of the surrounding medium. In a previous contribution (Lee & Stahler 2011), we determined this dynamical friction force when…
Models of core accretion assume that in the radiative zones of accreting gas envelopes, radiation diffuses. But super-Earths/sub-Neptunes (1-4$R_\oplus$, 2-20$M_\oplus$) point to formation conditions that are optically thin: their modest…
After protoplanets have acquired sufficient mass to open partial gaps in their natal protostellar disks, residual gas continues to diffuse onto horseshoe streamlines under effect of viscous dissipation, and meander in and out of the…
In the pebble accretion scenario, the pebbles that form planets drift inward from the outer disk regions, carrying water ice with them. At the water ice line, the water ice on the inward drifting pebbles evaporates and is released into the…
Pebble accretion is one of the major theories in planet formation. Aerodynamically small particles, called pebbles, are highly affected by the gas flow. A growing planet embedded in a protoplanetary disk induces three-dimensional (3D) gas…
In protoplanetary disks, small mm-cm-sized pebbles drift inwards which can aid planetary growth and influence the chemical composition of their natal disks. Gaps in protoplanetary disks can hinder the effective inward transport of pebbles…
The amount of nebular gas that a planet can bind is limited by its cooling rate, which is set by the opacity of its envelope. Accreting dust and pebbles contribute to the envelope opacity and, thus, influence the outcome of planet…
Gas-giant planets, like Jupiter and Saturn, acquire massive gaseous envelopes during the approximately 3 Myr-long lifetimes of protoplanetary discs. In the core accretion scenario, the formation of a solid core of around 10 Earth masses…
Pebble accretion has become a popular component to core accretion models of planet formation, and is especially relevant to the formation of compact, resonant terrestrial planetary systems. Pebbles initially form in the inner protoplanetary…
The streaming instability, as an example of instabilities driven by particle feedback on a gas flow, has been proven to have a major role in controlling the formation of planetesimals. Here, we present experiments to approach this situation…
A growing planet embedded in a protoplanetary disk induces three-dimensional gas flow, which exhibits a midplane outflow that can suppress dust accretion onto the planet and form global dust substructures (rings and gaps). Because analytic…
We show that equations of Newtonian hydrodynamics and gravity describing one-dimensional steady gas flow possess nonlinear periodic solutions. In the case of a zero-pressure gas the solution exhibits hydrodynamic similarity and is…
Condensible substances are nearly ubiquitous in planetary atmospheres. For the most familiar case-water vapor in Earth's present climate-the condensible gas is dilute, in the sense that its concentration is everywhere small relative to the…
The gravitational hydrodynamics of the primordial plasma with neutrino hot dark matter is considered as a challenge to the bottom-up cold dark matter paradigm. Viscosity and turbulence induce a top-down fragmentation scenario before and at…
The results of an extensive numerical study of the orbital dynamics of small bodies ranging from micron-sized dust grains to 1 km objects subject to gas drag and also the gravitational attraction of a non-uniform gaseous nebula are…
Recent observations found close-in planets with significant atmospheres of hydrogen and helium in great abundance. These are the so-called super-Earths and mini-Neptunes. Their atmospheric composition suggests that they formed early during…