Surprisingly fast motions in a dust disk

Timelike geodesic motions within the general relativistic gravitational field of the rigidly rotating disk of dust

The general relativistic motion of a test particle near a rigidly rotating disk of dust is investigated. Circular orbits within the plane of the disk ~centered on the rotation axis! are special cases of the geodesic motion. One finds that there is always a ~stable or unstable! circular orbit for positive angular momentum and a given radius. However, for sufficiently relativistic disks there are...

The Sun ’ S Dust Disk

designing a fast locking pll

a phase-locked loop (pll) based frequency synthesizer is an important circuit that is used in many applications, especially in communication systems such as ethernet receivers, disk drive read/write channels, digital mobile receivers, high-speed memory interfaces, system clock recovery and wireless communication system. other than requiring good signal purity such as low phase noise and low spu...

Dust Size Growth and Settling in a Protoplanetary Disk

We have studied dust evolution in a quiescent or turbulent protoplanetary disk by numerically solving coagulation equation for settling dust particles, using the minimum mass solar nebular model. As a result, if we assume an ideally quiescent disk, the dust particles settle toward the disk midplane to form a gravitationally unstable layer within 2× 103–4× 10yr at 1–30 AU, which is in good agree...

A submillimeter exponential disk in M 51 : evidence for an extended cold dust disk

A 850 µm map of the interacting spiral galaxy M 51 shows well-defined spiral arms, closely resembling the structures seen in CO and HI emission. However, most of the 850 µm emission originates in an underlying exponential disk, a component that has not been observed before in a face-on galaxy at these wavelengths. The scale-length of this disk is 5.45 kpc, which is somewhat larger than the scal...