相关论文: Formation of a Propeller Structure by a Moonlet in…

Here we demonstrate how Saturn could create its rings by itself, with the additional action of its axisymmetric magnetic field once appeared. A new mechanism for the origin of Saturn's rings is proposed for the first time. It includes the…

On June 12, 2007 the Cassini probe sent the images of a small moon of Saturn called Atlas which is located between the ring A and the small ring R/2004 S 1. These images have shown that the Atlas morphology is very different from other…

We present observations at optical wavelengths with the Cassini Spacecraft's Imaging Science System of the Phoebe ring, a vast debris disk around Saturn that seems to be collisionally generated by its irregular satellites. The analysis…

The formation of planets with gaseous envelopes takes place in protoplanetary accretion discs on time-scales of several millions of years. Small dust particles stick to each other to form pebbles, pebbles concentrate in the turbulent flow…

The structure of planetary systems around their host stars depends on their initial formation conditions. Massive planets will likely be formed as a consequence of rapid migration of planetesimals and low mass cores into specific trapping…

We examine the formation of planets around binary stars in light of the recently discovered systems Kepler 16, 34 and 35. We conduct hydrodynamical simulations of self gravitating disks around binary systems. The selected binary and disk…

The slow rotation of some young stars and the extreme rotation periods of some Ap stars have so far defied explanation. The absence of sufficiently efficient braking mechanisms for newly formed stars points to the star formation process…

We describe the current state of knowledge about Mercury's interior structure. We review the available observational constraints, including mass, size, density, gravity field, spin state, composition, and tidal response. These data enable…

Patterns of vorticity in the wake of a single rectangular winglet (vortex generator) embedded in a turbulent boundary layer have been studied using Stereoscopic Particle Image Velocimetry (SPIV). The winglet was mounted normally to a flat…

Saturn's rings are composed of icy grains, most in the mm to m size ranges, undergoing several collisions per orbit. Their collective behaviour generates a remarkable array of structure over many orders of magnitude, much of it not well…

Saturn is the only known planet to have coorbital satellite systems. In the present work we studied the process of mass accretion as a possible mechanism for coorbital satellites formation. The system considered is composed of Saturn, a…

Young protostellar discs provide the initial conditions for planet formation. The properties of these discs may be different from those of late-phase (T Tauri) discs due to continuing infall from the envelope and protostellar variability…

A planet of low mass orbiting in a two-dimensional gaseous disc generates a one-armed spiral wake. We explain this phenomenon as the result of constructive interference between wave modes in the disc, somewhat similar to the Kelvin wedge…

Spokes are localized clouds of fine particles that appear over the outer part of Saturn's B ring. Over the course of the Cassini Mission, the Imaging Science Subsystem (ISS) obtained over 20,000 images of the outer B ring, providing the…

We use N-body simulations to study the formation of rings in a disc galaxy by the impact of a small spherical companion. Both barred and nonbarred target discs are considered. We discuss the effect of the properties of the target disc…

Hydrodynamical simulations show that a pair of spiral arms can form in the disk around a rapidly-growing young star and that the arms are crucial in transporting angular momentum as the disk accretes material from the surrounding envelope.…

We discuss the physics of vortices in the circumstellar disks associated with young stellar objects. We elucidate the basic physical properties of these localized storm systems. In particular, we consider point vortices, linear vortices,…

The volume around the SN 1987A contains a variety of structures, not just the three rings glowing in recombination lines. Many of these are revealed by light echoes, so are mapped in three dimensions by our optical imaging of the SN…

A ring system consisting of two dense narrow rings has been discovered around Centaur Chariklo. The existence of these rings around a small object poses various questions, such as their origin, stability, and lifetime. In order to…

We study particle dynamics in local two-dimensional simulations of self-gravitating accretion discs with a simple cooling law. It is well known that the structure which arises in the gaseous component of the disc due to a gravitational…