Related papers: Can giant planets form by direct gravitational ins…
Forming giant planets by disk instability requires a gaseous disk that is massive enough to become gravitationally unstable and able to cool fast enough for self-gravitating clumps to form and survive. Models with simplified disk cooling…
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…
Doppler surveys have shown that more massive stars have significantly higher frequencies of giant planets inside $\sim$ 3 AU than lower mass stars, consistent with giant planet formation by core accretion. Direct imaging searches have begun…
Observational evidence suggests that gas disk instability may be responsible for the formation of at least some gas giant exoplanets, particularly massive or distant gas giants. With regard to close-in gas giants, Boss (2017) used the…
We estimate the maximum temperature at which planets can form via gravitational instability (GI) in the outskirts of early circumstellar disks. We show that due to the temperature floor set by the cosmic microwave background, there is a…
We use high resolution 3D SPH simulations to study the evolution of self-gravitating binary protoplanetary disks. Heating by shocks and cooling are included. We consider different orbital separations and masses of the disks and central…
The core-accretion mechanism for gas giant formation may be too slow to create all observed gas giant planets during reasonable gas disk lifetimes, but it has yet to be firmly established that the disk instability model can produce…
Both core accretion and disk instability appear to be required as formation mechanisms in order to explain the entire range of giant planets found in extrasolar planetary systems. Disk instability is based on the formation of clumps in a…
The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from…
The evolution of gravitationally unstable protoplanetary gaseous disks has been studied with the use of three-dimensional smoothed particle hydrodynamics simulations with unprecedented resolution. We have considered disks with initial…
Protoplanetary gas disks are likely to experience gravitational instabilites (GI's) during some phase of their evolution. Density perturbations in an unstable disk grow on a dynamic time scale into spiral arms that produce efficient outward…
Observational studies show that the probability of finding gas giant planets around a star increases with the star's metallicity. Our latest simulations of disks undergoing gravitational instabilities (GIs) with realistic radiative cooling…
Gravitational instability is one of considerable mechanisms to explain the formation of giant planets. We study the gravitational stability for the protoplanetary disks around a protostar. The temperature and Toomre's Q-value are calculated…
Gravitational fragmentation has been proposed as a mechanism for the formation of giant planets in close orbits around solar-type stars. However, it is debatable whether this mechanism can function in the inner regions (R<40 AU) of real…
We review the models and results of simulations of self-gravitating, gaseous protoplanetary disks in binary star systems. These models have been calculated by three different groups with three different computational methods, two…
We present the results of high resolution SPH simulations of the evolution of gravitationally unstable protoplanetary disks. We report on calculations in which the disk is evolved using a locally isothermal or adiabatic equation of state…
Direct imaging observations of planets revealed that wide-orbit ($>10$ au) giant planets exist even around subsolar-metallicity host stars and do not require metal-rich environments for their formation. A possible formation mechanism of…
Disk instability is an attractive yet controversial means for the rapid formation of giant planets in our solar system and elsewhere. Recent concerns regarding the first adiabatic exponent of molecular hydrogen gas are addressed and shown…
Observational evidence exists for the formation of gas giant planets on wide orbits around young stars by disk gravitational instability, but the roles of disk instability and core accretion for forming gas giants on shorter period orbits…
Context: Around 30 per cent of the observed exoplanets that orbit M dwarf stars are gas giants that are more massive than Jupiter. These planets are prime candidates for formation by disc instability. Aims: We want to determine the…