منابع مشابه
Chromospheric Activity of Rosat Discovered Weak-lined T Tauri Stars
We have started a high resolution optical observation program dedicated to the study of chromospheric activity in weak-lined T Tauri stars (WTTS) recently discovered by the ROSAT All-Sky Survey (RASS). It is our purpose to quantify the phenomenology of the chromospheric activity of each star determining stellar surface fluxes in the more important chromospheric activity indicators (Ca ii H & K,...
متن کاملSearching for chromospheric Lyman-α emission in A–F stars from IUE high resolution spectra
With the aim of locating the boundary for the onset of chromospheric emission in the H-R diagram we have undertaken a spectroscopic study of the hydrogen Ly-α, using the IUE short wavelength spectrograph in the high resolution mode. We report here on the analysis of IUE spectra of 11 A–F type stars. We have detectedLy-α emission in stars as early asA7 (B–V = 0.19), establishing a new limit for ...
متن کاملMass Outflow and Chromospheric Activity of Red Giant Stars in Globular
High resolution spectra of 123 red giant stars in the globular cluster M13 and 64 red giant stars in M92 were obtained with Hectochelle at the MMT telescope. Emission and line asymmetries in Hα, and Ca II K are identified, characterizing motions in the extended atmospheres and seeking differences attributable to metallicity in these clusters and M15. On the red giant branch, emission in Hα gene...
متن کاملOn the link between rotation, chromospheric activity and Li abundance in subgiant stars
The connection rotation–CaII emission flux–lithium abundance is analyzed for a sample of bona fide subgiant stars, with evolutionary status determined from HIPPARCOS trigonometric parallax measurements and from the Toulouse–Geneva code. The distribution of rotation and CaII emission flux as a function of effective temperature shows a discontinuity located rather around the same spectral type, F...
متن کاملMass Outflow and Chromospheric Activity of Red Giant Stars in Globular Clusters
High resolution spectra of 110 selected red giant stars in the globular cluster M15 (NGC 7078) were obtained with Hectochelle at the MMT telescope in 2005 May, 2006 May, and 2006 October. Echelle orders containing Hα and Ca II H & K are used to identify emission and line asymmetries characterizing motions in the extended atmospheres. Emission in Hα is detected to a luminosity of log(L/L⊙) = 2.3...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1976
ISSN: 0074-1809
DOI: 10.1017/s0074180900008408