Related papers: Constraining the initial planetary population in t…
Recent ALMA observations may indicate a surprising abundance of sub-Jovian planets on very wide orbits in protoplanetary discs that are only a few million years old. These planets are too young and distant to have been formed via the Core…
Recent direct imaging discoveries suggest a new class of massive, distant planets around A stars. These widely separated giants have been interpreted as signs of planet formation driven by gravitational instability, but the viability of…
Transitional disks, protoplanetary disks with deep and wide central gaps, may be the result of planetary sculpting. By comparing numerical planet-opening-gap models with observed gaps, we find systems of 3-6 giant planets are needed in…
The detection of many extrasolar gas giants with high eccentricities indicates that dynamical instabilities in planetary systems are common. These instabilities can alter the orbits of gas giants as well as the orbits of terrestrial planets…
Observations support the hypothesis that gas disk gravitational instability might explain the formation of massive or wide-orbit gas giant exoplanets. The situation with regard to Jupiter-mass exoplanets orbiting within $\sim$ 20 au is more…
We develop a simple model for computing planetary formation based on the core instability model for the gas accretion and the oligarchic growth regime for the accretion of the solid core. In this model several planets can form…
Core accretion and disk instability have traditionally been regarded as the two competing possible paths of planet formation. In recent years, evidence have accumulated in favor of core accretion as the dominant mode, at least for close-in…
It has recently been noted that many discs around T Tauri stars appear to comprise only a few Jupiter-masses of gas and dust. Using millimetre surveys of discs within six local star-formation regions, we confirm this result, and find that…
We present a suite of three dimensional radiative gravitational hydrodynamics models suggesting that binary stars may be quite capable of forming planetary systems similar to our own. The new models with binary companions do not employ any…
Gravitational torques between a planet and gas in the protoplanetary disk result in orbital migration of the planet, and are likely to play an important role in the formation and early evolution of planetary systems. For masses comparable…
The recent discoveries of massive planets on ultra-wide orbits of HR 8799 (Marois et al. 2008) and Fomalhaut (Kalas et al. 2008) present a new challenge for planet formation theorists. Our goal is to figure out which of three giant planet…
Gap formation by giant planets in self-gravitating disks may lead to a gravitational edge instability (GEI). We demonstrate this GEI with global 3D and 2D self-gravitating disk-planet simulations using the ZEUS, PLUTO and FARGO hydrodynamic…
Secular gravitational instability (GI) is one of the promising mechanisms for creating annular substructures and planetesimals in protoplanetary disks. We perform numerical simulations of the secular GI in a radially extended disk with…
We investigate the gravitational interaction of a Jovian mass protoplanet with a gaseous disc with aspect ratio and kinematic viscosity expected for the protoplanetary disc from which it formed. Different disc surface density distributions…
In a further development of a deterministic planet-formation model (Ida & Lin 2004), we consider the effect of type-I migration of protoplanetary embryos due to their tidal interaction with their nascent disks. During the early embedded…
The increasing number of newly detected exoplanets at short orbital periods raises questions about their formation and migration histories. A particular puzzle that requires explanation arises from one of the key results of the Kepler…
A new model for the formation of Jovian planets is proposed. We consider planets forming at large distances from a protostar (>100 AU) through direct fragmentation of a gas cloud, by the same formation mechanism as wide stellar and brown…
We carry out a large set of very high resolution, three dimensional smoothed particle hydrodynamics (SPH) simulations describing the evolution of gravitationally unstable gaseous protoplanetary disks. We consider a broad range of initial…
Disc instability (DI) is a model aimed at explaining the formation of companions through the fragmentation of the circumstellar gas disc. Furthermore, DI could explain the formation of part of the observed exoplanetary population. We aim to…
Recent imaging observations with ALMA and other telescopes found widespread signatures of planet presence in protoplanetary discs at tens of au separations from their host stars. Here we point out that the presence of very massive planets…