Results 191 to 200 of about 1,966 (233)

The Solar Photosphere

1965
The sun has a radius R = 7 × 105 km, and is situated about rE = 1.5 × 108 km from the earth. Since the mass of the sun is M= 2 × 1033 g the average density can be determined as 1.4 gcm-3. However, the density changes from 70 gem-3 at the solar centre, where the temperature is 14 × 106 °K, to 10-7 gem-3 in the photosphere.
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Structure of the Solar Photosphere

Space Science Reviews, 1998
The majority of measured solar abundances refer to the solar photosphere. In general, when determining photospheric abundances a plane-parallel atmosphere and LTE are assumed. However, the photosphere is structured by granulation, magnetic fields and p-modes. They change line profiles by the thermal inhomogeneities and wavelength shifts they introduce.
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Solar rotation: The photospheric height gradient

Solar Physics, 1972
For selected pairs of Fraunhofer lines the height of formation has been calculated corresponding to that portion of the profile intercepted by the magnetograph exit slits. A photospheric height discrimination of 150–300 km is realized. In 1971 simultaneous measurements of equatorial angular velocity from spectroscopic displacements of these line pairs ...
W. Livingston, R. Milkey
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Temperature variations in the solar photosphere

Solar Physics, 1973
Detailed LTE calculations were made of the sensitivities of some Fraunhofer lines to local variations of the effective temperature of the Sun, taking also into account the effects of local variations of the microturbulence. The temperature sensitivities show a clear dependence upon the mean optical depth at which lines originate and upon the binding ...
B. Caccin, A. Donati-Falchi, R. Falciani
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Sub-photosphere to Solar Atmosphere Connection

Space Science Reviews, 2013
Magnetic fields extend from the solar interior through the atmosphere. The formation and evolution of active regions can be studied by measuring subsurface flows with local helioseismology. The emergence of magnetic flux from the solar convection zone is associated with acoustic perturbation signatures.
Rudolf Komm, Ineke De Moortel, Yuhong Fan, Stathis Ilonidis, Oskar Steiner   +4 more
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The solar photospheric abundance of iron

Solar Physics, 1975
A new value of the solar photospheric abundance of iron, independent of line-shape parameters, is derived.
E. Bi�mont, N. Grevesse
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4.1.1.4 Solar photosphere and chromosphere

2009
Traditionally, the atmosphere of the Sun has been divided into four layers, starting with the photosphere at the bottom, followed by the chromosphere, the transition region, and the corona as the outermost region. The photosphere is a layer of only a few hundred kilometers thickness in which the temperature drops outwards from around 6000 K at the ...
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Temperature variations in the solar photosphere

Solar Physics, 1974
From the variations in equivalent width of a selected set of Fraunhofer lines, we derived the variation of effective temperature and microturbulence velocity between the equator and the regions at heliographic latitude of ∼- 72°. The reliability of the results (ΔT/T = 0 ± 0.6%, Δξ/ξ = 6% ± 13%) needs further investigations, but from the analysis of our
R. Falciani, M. Rigutti, G. Roberti
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The photospheric solar oxygen project

2015
International ...
Caffau, E., Ludwig, H.-G., Steffen, M., Livingston, W., Bonifacio, P., Malherbe, J.-M., Doerr, H.-P., Schmidt, W.   +7 more
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Temperature fluctuations in the solar photosphere

Solar Physics, 1969
The general problem of interpreting granulation data, in particular Edmonds' r.m.s. intensity fluctuation distribution against heliocentric angle θ, is discussed.
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