Related papers: Evolutionary constraints on the planetary hypothes…
We examine the distribution of transition discs as a function of mm flux. We confirm that as expected in any model in which most primordial discs turn into transition discs and in which mm flux declines with time, transition discs have…
Recent spectral observations by the Spitzer Space Telescope (SST) reveal that some discs around young ($\sim {\rm few} \times 10^6$ yr old) stars have remarkably sharp transitions to a low density inner region in which much of the material…
Planet migration in protoplanetary discs plays an important role in the longer term evolution of planetary systems, yet we currently have no direct observational test to determine if a planet is migrating in its gaseous disc. We explore the…
Recent ALMA observations indicate that the majority of bright protoplanetary discs show signatures of young moderately massive planets. I show that this result is paradoxical. The planets should evolve away from their observed states by…
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…
In protoplanetary discs, planetary cores must be at least 0.1 earth mass at 1 au for migration to be significant; this mass rises to 1 earth mass at 5 au. Planet formation models indicate that these cores form on million year timescales. We…
In this paper we study the evolution of radiative fluxes, flux radii and observable dust masses in protoplanetary discs, in order to understand how these depend on the angular momentum budget and on the assumed heat sources. We use a model…
Planetary migration is essential to explain the observed mass-period relation for exoplanets. Without some stopping mechanism, the tidal, resonant interaction between planets and their gaseous disc generally causes the planets to migrate…
Planets orbiting a planetesimal circumstellar disc can migrate inward from their initial positions because of dynamical friction between planets and planetesimals. The migration rate depends on the disc mass and on its time evolution.…
Photoevaporative disc winds play a key role in our understanding of circumstellar disc evolution, especially in the final stages, and they might affect the planet formation process and the final location of planets. The study of transition…
We quantify the utility of large radial velocity surveys for constraining theoretical models of Type II migration and protoplanetary disk physics. We describe a theoretical model for the expected radial distribution of extrasolar planets…
Planets have been detected around a variety of stars, including low-mass objects, such as brown dwarfs. However, such extreme cases are challenging for planet formation models. Recent sub-millimeter observations of disks around brown dwarf…
Context.Transition disks are believed to be the final stages of protoplanetary disks, during which a forming planetary system or photoevaporation processes open a gap in the inner disk, drastically changing the disk structure. From…
Transition disks with large dust cavities around young stars are promising targets for studying planet formation. Previous studies have revealed the presence of gas cavities inside the dust cavities hinting at recently formed, giant…
Transition disks are protoplanetary disks with inner depleted dust cavities and excellent candidates to investigate the dust evolution under the existence of a pressure bump. A pressure bump at the outer edge of the cavity allows dust…
Many extra-solar planets discovered over the past decade are gas giants in tight orbits around their host stars. Due to the difficulties of forming these `hot Jupiters' in situ, they are generally assumed to have migrated to their present…
Recent ALMA observations indicate that while a range of disk sizes exist, typical disk radii are small, and that radial dust drift affects the distribution of solids in disks. Here we explore the consequences of these features in planet…
Transitional disks represent a short stage of the evolution of circumstellar material. Studies of dust grains in these objects can provide pivotal information on the mechanisms of planet formation. Dissimilarities in the spatial…
We present N-body simulations of planetary system formation in thermally-evolving, viscous disc models. The simulations incorporate type I migration (including corotation torques and their saturation), gap formation, type II migration, gas…
The unusual properties of transition objects (young stars with an optically thin inner disc surrounded by an optically thick outer disc) suggest that significant disc evolution has occured in these systems. We explore the nature of these…