相关论文: Circumstellar Disks
We present results of a study aimed at deriving fundamental properties of circumstellar debris disks from observed infrared to submillimeter spectral energy distributions. This investigation is motivated by increasing telescope/detector…
During their formative stages, giant planets are fed by infalling material sourced from the background circumstellar disk. Due to conservation of angular momentum, the incoming gas and dust collects into a circumplanetary disk that…
The radial distribution of mass in a disk galaxy is strongly constrained by its rotation curve. The separate contributions from the individual stellar populations and dark matter (DM) are not easily disentangled, however, especially since…
Different ways of the determination of masses of galactic disks, based on the kinematic data, are briefly discussed. The analysis of the rotation curves which reach maximum inside of a disk, and N-body modeling, reproducing the rotation…
Observations of circumstellar disks around stars as a function of stellar properties such as mass, metallicity, multiplicity, and age, provide constraints on theories concerning the formation and evolution of planetary systems. Utilizing…
Molecular lines hold valuable information on the physical and chemical composition of disks around young stars, the likely progenitors of planetary systems. This invited contribution discusses techniques to calculate the molecular emission…
By making spectral absorption-line observations of disk galaxies at intermediate inclinations, we have been able to determine the amplitude of their constituent stars' random motions in three dimensions. This full measure of the shape of…
A detailed understanding of the physics of star and planet formation requires study of individual objects as well as statistical assessment of global properties and evolutionary trends. Observational investigations of circumstellar material…
We derive hydrostatic, radiative equilibrium models for passive disks surrounding T Tauri stars. Each disk is encased by an optically thin layer of superheated dust grains. This layer re-emits directly to space about half the stellar energy…
The problem of dynamical heating of galactic discs by spiral density waves is discussed using the shearing sheet model. The secular evolution of the disc is described quantitatively by a diffusion equation for the distribution function of…
We have completed a systematic survey for disks around young brown dwarfs and very low mass stars. By choosing a well-defined sample and by obtaining sensitive thermal IR observations, we can make an unbiased measurement of the disk…
Multi-wavelength spectroscopy can be used to constrain the dust and gas properties in debris disks. Circumstellar dust absorbs and scatters incident stellar light. The scattered light is sometimes resolved spatially at visual and…
The disks that surround young stars are mostly composed of molecular gas, which is harder to detect and interpret than the accompanying dust. Disk mass measurements have therefore relied on large and uncertain extrapolations from the dust…
We present a detailed, self-consistent model of radiatively driven stellar outflows which couples the radiative transfer and hydrodynamics equations. The circumstellar envelope, which consists of gas and dust, is described as a…
The excess emission seen in spectral energy distributions (SEDs) is commonly used to infer the properties of the emitting circumstellar dust in protoplanetary and debris discs. Most notably, dust size distributions and details of the…
Mass loss appears to be a common phenomenon among disk-accreting astrophysical systems. An outflow emanating from an accretion disk can act as a sink for mass, angular momentum and energy and can therefore alter the dissipation rates and…
The formation of galactic discs and the efficiency of star formation within them are issues central to our understanding of galaxy formation. We have developed a detailed and versatile model of disc formation which combines the strengths of…
Circumstellar disks are an essential ingredient of the formation of low-mass stars. It is unclear, however, whether the accretion-disk paradigm can also account for the formation of stars more massive than about 10 solar masses, in which…
The circular velocities of the inner region of disk galaxies are predicted by standard physics but velocities beyond the stellar disks are not consistent with Newtonian physics if the material there is in stable circular orbits. However,…
Context. The analysis of observations of circumstellar disks around young stellar objects is often based on models with a smooth and continuous density distribution. However, spatially resolved observations with increasing angular…