The effects of disc warping on the inclination of planetary orbits
MNRAS (2013)
Protoplanets with core masses below the critical mass fill in their Roche lobe
Monthly Notices of the Royal Astronomical Society 418:3 (2011) 1928-1934
Abstract:
We study the evolution of a protoplanet of a few earth masses embedded in a protoplanetary disc. If we assume that the atmosphere of the protoplanet, i.e. the volume of gas in hydrostatic equilibrium bound to the core, has a surface radius smaller than the Roche lobe radius, we show that it expands as it accretes both planetesimals and gas at a fixed rate from the nebula until it fills in the Roche lobe. The evolution occurs on a time-scale shorter than the formation or migration time-scales. Therefore, we conclude that protoplanets of a few earth masses have an atmosphere that extends to the Roche lobe surface, where it joins on to the nebula. This is true even when the Bondi radius is smaller than the Roche lobe radius. This is in contrast to the commonly used models in which the static atmosphere extends up to the Bondi radius and is surrounded by a cold accretion flow. As a result, any calculation of the tidal torque exerted by the disc on to the protoplanet should exclude the material present in the Roche lobe, since it is bound to the protoplanet. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.Disk dynamics and planet migration
EAS Publications Series 41 (2010) 209-218
Abstract:
We review models of protoplanetary disks. In the earlier stages of evolution, disks are subject to gravitational instabilities that redistribute mass and angular momentum on short timescales. Later on, when the mass of the disk is below ten percent or so of that of the central star, accretion occurs through the magnetorotational instability. The parts of the disks that are not ionized enough to couple to the magnetic field may not accrete or accrete inefficiently. We also review theories of planet migration. Tidal interaction between a disk and an embedded planet leads to angular momentum exchange between the planetary orbital motion and the disk rotation. This results in low mass planets migrating with respect to the gas in the disk, while massive planets open up a gap in the vicinity of their orbit and migrate in as the disk is accreted. © EAS, EDP Sciences, 2010.Eccentricity pumping of a planet on an inclined orbit by a disc
Monthly Notices of the Royal Astronomical Society 404:1 (2010) 409-414
Abstract:
In this paper, we show that the eccentricity of a planet on an inclined orbit with respect to a disc can be pumped up to high values by the gravitational potential of the disc, even when the orbit of the planet crosses the disc plane. This process is an extension of the Kozai effect. If the orbit of the planet is well inside the disc inner cavity, the process is formally identical to the classical Kozai effect. If the planet's orbit crosses the disc but most of the disc mass is beyond the orbit, the eccentricity of the planet grows when the initial angle between the orbit and the disc is larger than some critical value which may be significantly smaller than the classical value of 39{ring operator}. Both the eccentricity and the inclination angle then vary periodically with time. When the period of the oscillations of the eccentricity is smaller than the disc lifetime, the planet may be left on an eccentric orbit as the disc dissipates. © 2010 The Authors. Journal compilation. © 2010 RAS.On the dynamics of multiple systems of hot super-Earths and Neptunes: Tidal circularization, resonance and the HD 40307 system
Monthly Notices of the Royal Astronomical Society 405:1 (2010) 573-592