منابع مشابه
Stellar Ages from Stellar Rotation
Our ability to determine stellar ages from measurements of stellar rotation, hinges on how well we can measure the dependence of rotation on age for stars of different masses. Rotation periods for stars in open clusters are essential to determine the relations between stellar age, rotation, and mass (color). Until recently, ambiguities in v sin i data and lack of cluster membership information,...
متن کاملStellar ages from asteroseismology
Asteroseismology has been recognized for a long time as a very powerful mean to probe stellar interiors. The oscillations frequencies are closely related to stellar internal structure properties via the density and the sound speed profiles. Since these properties are in turn tightly linked with the mass and evolutionary state, we can expect to determine the age and mass of a star from the compa...
متن کاملConfronting Substellar Theoretical Models with Stellar Ages
By definition, brown dwarfs never reach the main-sequence, cooling and dimming over their entire lifetime, thus making substellar models challenging to test because of the strong dependence on age. Currently, most brown dwarfs with independently determined ages are companions to nearby stars, so stellar ages are at the heart of the effort to test substellar models. However, these models are onl...
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...
متن کاملStellar Populations and Ages of M82 Super Star Clusters
We present high signal-to-noise optical spectra of two luminous super star clusters in the starburst galaxy M82. The data for cluster F and the nearby, highly reddened cluster L were obtained with the William Herschel Telescope (WHT) at a resolution of 1.6 Å. The blue spectrum (3250–5540Å) of cluster F shows features typical of midB stars. The red spectra (5730–8790Å) of clusters F and L show t...
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ژورنال
عنوان ژورنال: The Astronomical Journal
سال: 1962
ISSN: 0004-6256
DOI: 10.1086/108635