منابع مشابه
Differential Radial Velocities and Stellar Parameters of Nearby Young Stars
Radial velocity searches for substellar mass companions have focused primarily on stars older than 1 Gyr. Increased levels of stellar activity in young stars hinders the detection of solar system analogs and therefore there has been a prejudice against inclusion of young stars in radial velocity surveys until recently. Adaptive optics surveys of young stars have given us insight into the multip...
متن کاملThe stellar dynamics and mass of NGC 1316 using the radial velocities of Planetary Nebulae
We present a study of the kinematics of the outer regions of the early-type galaxy NGC 1316, based on radial velocity measurements of 43 planetary nebulae as well as deep integrated-light absorption line spectra. The smoothed velocity field of NGC 1316 indicates fast rotation at a distance of 16 kpc, possibly associated with an elongated feature orthogonal to the inner dust lanes. The mean squa...
متن کاملGAIA Spectroscopy and Radial Velocities
GAIA spectroscopic and radial velocity performancies are reviewed on the base of groundbased test observations and simulations. The prospects for accurate analysis of stellar atmospheres (temperature, gravity, chemical abundances, rotation, peculiarities) and precise radial velocities (single stars, binaries, pulsating stars) are colorful provided the spectral dispersion is high enough. A highe...
متن کاملCusped Spherical Stellar Systems with Anisotropic Velocities
Spherical models with constant velocity anisotropy β have distribution functions depending on binding energy E and angular momentum L of the form f (E, L) = L−2β fE(E). An inversion for the unknown function fE (E) is straightforward to derive and reduces to Eddington’s famous algorithm for isotropic models (β = 0). Importantly, if the anisotropy parameter of the model is a half-integer constant...
متن کاملRadiative diffusion in stellar atmospheres : diffusion velocities
Aims. The present paper addresses some of the problems in the buildup of element stratification in stellar magnetic atmospheres due to microscopic diffusion, in particular the redistribution of momentum among the various ionisation stages of a given element and the calculation of diffusion velocities in the presence of inclined magnetic fields. Methods. We have considerably modified and extende...
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ژورنال
عنوان ژورنال: Nature
سال: 1932
ISSN: 0028-0836,1476-4687
DOI: 10.1038/130836a0