Results 91 to 100 of about 143 (112)

PREDICTED ULTRAVIOLET SPECTRA FROM STELLAR CHROMOSPHERES

Journal of Quantitative Spectroscopy and Radiative Transfer, 1968
Abstract 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
openaire   +2 more sources

Progress in Stellar Chromospheres Observed with the IUE Satellite

Publications of the Astronomical Society of the Pacific, 1983
S L Baliunas
exaly   +2 more sources

Solar and stellar chromospheric contrast

Solar Physics, 1994
We 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, Sergio R. Restaino, Stephen L. Keil   +2 more
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Stellar chromospheric temperatures

Astrophysics and Space Science, 1983
The 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

1986
The 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

2008
Gravitational 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, W. Dean Pesnell, L. Drake Deming, Martin Snow, Travis S. Metcalfe, Tom Woods, Brigette Hesman   +6 more
openaire   +1 more source

Stellar Chromospheres: The Source of UV Emission

2019
The 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

1981
In 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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Stellar chromospheres.

Science (New York, N.Y.), 2010
Besides being of intrinsic interest, these outer stellar envelopes provide very useful astrophysical tools. ; © 1966 American Association for the Advancement of Science.
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Analysis of solar and stellar chromospheric calcium and magnesium lines

Advances in Space Research, 1986
Abstract 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, G. Simon, A. Mangeney, O. Clary, F. Praderie, Z. Mouradian   +5 more
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