Results 111 to 120 of about 164 (131)
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PREDICTED ULTRAVIOLET SPECTRA FROM STELLAR CHROMOSPHERES
Journal of Quantitative Spectroscopy and Radiative Transfer, 1968Abstract Perhaps the most tangible evidence of the existence and structure of postulated stellar chromospheres of otherwise relatively cool stars would be the detection of an intense ultraviolet spectrum. The solar case for which a variety of measurements is available now reveals that the observed spectrum depends in a very complex and not thoroughly
L. Oster, N.P. Patterson
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Solar and stellar chromospheric contrast
Solar Physics, 1994We present an analysis of disk-integrated spectra of the Caii K line (3933.68 A). The selection of parameters in the line profile, and the correlations between them, follow the work of Smith (1960), but represent an innovative aspect in the fact that our data are spatially integrated.
Robert A. Donahue +2 more
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Progress in Stellar Chromospheres Observed with the IUE Satellite
Publications of the Astronomical Society of the Pacific, 1983exaly +2 more sources
Stellar chromospheric temperatures
Astrophysics and Space Science, 1983The emission doublet 2800 Mgii of stellar chromospheric origin is always stronger than the emission in the Lα line of hydrogen. At the same time, the ratio of their fluxes,Q=F(Mgii)/F(Lα), varies over a wide range— from 2 up to 20 in stars of one and the same type.
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Stellar Chromospheres, Coronae, and Winds
1986The three subjects listed in the title of this chapter were originally defined for phenomena that are observed in the Sun. Observations of other stars have now been made at a wide range of wavelengths and have revealed that one or more of these phenomena are present in stars of every class.
J. P. Cassinelli, K. B. MacGregor
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Chromospheric Lines as Diagnostics of Stellar Oscillations
2008Gravitational waves in the chromosphere, theorized as early as 1963 [10], are thoroughly explored in the more recent papers by [7, 8]. Theory predicts that the convective overshoot in the upper photosphere and low chromosphere will readily excite gravity waves.
Diane B. Paulson +6 more
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Stellar Chromospheres: The Source of UV Emission
2019The lower layer of a star’s atmosphere, its photosphere, has a thermal structure that decreases outward controlled by the balance of radiative and convection heat from below and the loss of radiation to space. With increasing height in a stellar atmosphere, magnetic heating processes become important in the energy balance, forcing the temperature to ...
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Theories of Heating of Solar and Stellar Chromospheres
1981In the outer atmosphere of stars a rise of the kinetic temperature to values above Teff is possible only if a large and persistent amount of mechanical heating is present. Constraints derived from empirical chromosphere models allow selection of important heating mechanisms from among a great number of possible processes.
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Analysis of solar and stellar chromospheric calcium and magnesium lines
Advances in Space Research, 1986Abstract Using a combination of ground-based and satellite observations of the Sun, we determine several parameters of CaII H, K and MgII h, k chromospheric lines. From simple chromospheric models (similar to those proposed by T. Ayres) we establish semi-empirical laws obeyed by some of these parameters.
P. Lemaire +5 more
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Energy Balance in Solar and Stellar Chromospheres
1981The spectrum from a specific region of the sun or from a star can be used to determine the temperature-density stratification and other physical properties of the emitting atmospheric layers. We need such a description of the atmosphere in order to understand the causes of solar activity and the nature of various stellar phenomena.
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