相关论文: Collisional Cascade Caclulations for Irregular Sat…

Since the 1980's it has been becoming increasingly clear that the Solar System's irregular satellites are collisionally evolved. We derive a general model for the collisional evolution of an irregular satellite swarm and apply it to the…

The planet candidate Fomalhaut b is bright in optical light but undetected in longer wavelengths, requiring a large, reflective dust cloud. The most recent observations find an extremely eccentric orbit (e ~ 0.8), indicating that Fomalhaut…

We investigate formation mechanisms for icy super-Earth mass planets orbiting at 2-20 AU around 0.1-0.5 solar mass stars. A large ensemble of coagulation calculations demonstrates a new formation channel: disks composed of large…

Recent observations of exoplanets by direct imaging, reveal that giant planets orbit at a few dozens to more than a hundred of AU from their central star. The question of the origin of these planets challenges the standard theories of…

By logging encounters between planetesimals and planets we compute the distribution of encounters in a numerically integrated two planet system that is migrating due to interactions with an exterior planetesimal belt. Capture of an…

We consider the long-term collisional and dynamical evolution of solid material orbiting in a narrow annulus near the Roche limit of a white dwarf. With orbital velocities of 300 km/sec, systems of solids with initial eccentricity $e…

Extraterrestrial intelligences are speculated to surround stars with structures to collect their energy or to signal distant observers. If they exist, these most likely are megaswarms, vast constellations of satellites (elements) in orbit…

We investigate pathways for the formation of icy super-Earth mass planets orbiting at 125-250 AU around a 1 solar mass star. An extensive suite of coagulation calculations demonstrates that swarms of 1 cm to 10 m planetesimals can form…

Catastrophic planetesimal disruptions offer a unique opportunity to study and characterize large planetesimal populations in exoplanetary systems that are not currently detectable by modern observatories. The unexpected discovery of a…

The apparent detection of an exoplanet orbiting Fomalhaut was announced in 2008. However, subsequent observations of Fomalhaut b raised questions about its status: Unlike other exoplanets, it is bright in the optical and nondetected in the…

Fomalhaut is a bright star 7.7 parsecs (25 light years) from Earth that harbors a belt of cold dust with a structure consistent with gravitational sculpting by an orbiting planet. Here, we present optical observations of an exoplanet…

We investigated the probability that an inelastic collision of planetesimals within the Hill sphere of the Jovian planets could explain the presence and orbits of observed irregular satellites. Capture of satellites via this mechanism is…

We report on a search for low mass companions within 10 AU of the star Fomalhaut, using narrow band observations at 4.05 microns obtained with the Apodizing Phase Plate (APP) coronagraph on the VLT/NaCo. Our observations place a model…

We investigated the probability that an inelastic collision of planetesimals within the Hill sphere of the Jovian planets could explain the presence and orbits of observed irregular satellites. Capture of these satellites via this mechanism…

We analyze two new sets of coagulation calculations for solid particles orbiting within the terrestrial zone of a solar-type star. In models of collisional cascades, numerical simulations demonstrate that the total mass, the mass in 1 mm…

A candidate < 3 Jupiter mass, extrasolar planet was recently imaged by Kalas et al. (2008) using HST/ACS at 12.7" (96 AU) separation from the nearby (d = 7.7 pc) young (~200 Myr) A2V star Fomalhaut. Here we report results from M-band (4.8…

We investigate the migration of massive extrasolar planets due to gravitational interaction with a viscous protoplanetary disc. We show that a model in which planets form at 5 AU at a constant rate, before migrating, leads to a predicted…

The dynamical evolution of planetary systems leaves observable signatures in debris disks. Optical images trace micron-sized grains, which are strongly affected by stellar radiation and need not coincide with their parent body population.…

We use a hybrid, multiannulus, n-body-coagulation code to investigate the growth of km-sized planetesimals at 0.4-2 AU around a solar-type star. After a short runaway growth phase, protoplanets with masses of roughly 10^26 g and larger form…

We use a multiannulus planetesimal accretion code to investigate the growth of icy planets in the outer regions of a planetesimal disk. In a quiescent minimum mass solar nebula, icy planets grow to sizes of 1000--3000 km on a timescale t =…