Results 141 to 150 of about 146,288 (166)

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
openaire   +1 more source

Stellar Chromospheres: The Source of UV Emission

Lecture Notes in Physics, 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 ...
Jeffrey Linsky
exaly   +2 more sources

Addendum - Detection of Mass Loss in Stellar Chromospheres

Astrophysical Journal, 1980
R E Stencel
exaly   +2 more sources

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.
openaire   +1 more source

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
openaire   +1 more source

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

Solar and stellar chromospheres

2005
This review attempts to highlight two fundamental and complementary aspects of the chromospheric phenomenon; viz., global properties of stellar chromospheres and their variation among the stars, and the underlying fine structure that affects or determines these global properties.
openaire   +1 more source

Stellar Chromospheres, Coronae, and Winds (Invited Review)

Astrophysics and Space Science, 1986
Within the last few years there have been important advances in our understanding of the chromospheres, coronae, and winds of late-type stars. This progress has been the result of ultraviolet and X-ray observations obtained from space with the International Ultraviolet Explorer andEinstein satellites. In addition, ground-based astronomy has contributed
openaire   +1 more source

Stellar Chromospheres, Coronae, and Winds

1992
Chromospheres, coronae, and winds similar to those observed on the Sun have been detected in a variety of cool stars. In many cases, especially for main-sequence stars, there is good evidence that the processes leading to non-radiative plasma heating and wind acceleration are the same as for the Sun, although the radiative losses from stellar ...
openaire   +1 more source

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.
openaire   +1 more source