The Double Reversal in the Cores of the Fraunhofer H and K Lines.

Goldberg, Leo; Mohler, Orren C.; Müller, Edith A.

doi:10.1086/146600

Cited by 33 publications

(6 citation statements)

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“…Since The computed line profiles at three heliocentric angles are compared with the observed mean profiles of Goldberg et al (1959). Figure 4, the averaged profiles at #--1, 0.5, 0.2 are compared with the observed mean profiles of Goldberg et al (1959). Although not in complete agreement, the computed profiles exhibit the correct qualitative features.…”

Section: A Two-dimensional Three-component Modelmentioning

confidence: 93%

“…The line center opacity has been assumed depth independent in each component because, following the argument of the previous section, it was felt that the assumptions required to calculate a depth dependence consistent with the source function variations in each component were too unreliable at this stage. Since The computed line profiles at three heliocentric angles are compared with the observed mean profiles of Goldberg et al (1959). Figure 4, the averaged profiles at #--1, 0.5, 0.2 are compared with the observed mean profiles of Goldberg et al (1959).…”

Section: A Two-dimensional Three-component Modelmentioning

confidence: 99%

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A three-component model for the formation of the chromospheric Caii K line

Wilson

1970

Sol Phys

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A recent two-component model for the formation of the Ca II K line in the solar chromosphere put forward by Beebe and Johnson is discussed. Although this model is a great advance on existing one-component models, it is pointed out that observations require a minimum of three components in order to understand the formation of the K2 peaks.In order to make some progress in the study of multicomponent models an adaptation of the empirical (or analytic) approach is suggested. This relates the line source function directly to observations and places a secondary importance (at this stage) on the synthetic approach to the problem. A model is obtained which is in adequate agreement with observed mean profiles and its features are briefly discussed.

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Section: A Two-dimensional Three-component Modelmentioning

confidence: 93%

Section: A Two-dimensional Three-component Modelmentioning

confidence: 99%

A three-component model for the formation of the chromospheric Caii K line

Wilson

1970

Sol Phys

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“…and where A2 v = 3.88 K (s) F o (Griem, 1960) (5) (2s) 4 K(s) = 5.5 • 10 -5 s2_ 4 (6) with s being the principal quantum number, and F o = 1.25 x 10-9he 2/3 .…”

Section: Stark Broadening Of Hementioning

confidence: 99%

Spectral analysis of sunspot flares

Machado¹,

Seibold²

1973

Sol Phys

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We have qualitatively analyzed, in the H and K lines spectral region, 31 flares covering part of umbrae or penumbrae of sunspots. A strong narrowing of the emission lines has been observed over the umbrae, and the lines are, in general, much weaker than in common flares suggesting that the optical thickness is quite low in these parts. We have calculated the Stark broadening of the He line from the general theory, and it has been applied to obtain the electron density in 9 flare spectra. In all cases it has been found that n~> 1013 cm -3. Goldberg's method has been applied to find the kinetic temperature from the H and K lines of Ca II, and from the ratio between the central intensities of the lines we have calculated the optical thickness in the K line. Much evidence supports the assumption that the flare emission is highly diluted* * in the cases considered, and we propose a two-component model for the calcium emission lines.

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“…For radiative excitation from the 48 and 3d states to the 4p state, rates have been derived from data on absolute intensities at the centre of the disk in Hand K and their centre-limb variations given by Goldberg, Mohler, and Muller (1959) and from data on the intensity in A. 8542 shown in the Utrecht Atlas (Minnaert, Mulders, and Houtgast 1940).…”

Section: (A) Hydrogenmentioning

confidence: 99%

Excitation of Hydrogen and Ca II Under Chromospheric Conditions

Giovanelli¹

1967

Aust. J. Phys.

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SummaryMethods are described for calculating excitation conditions in a hot gas in the absence of local thermodynamic equilibrium, taking self-absorption into account, in the approximation that excitation is uniform throughout the medium. The equilibrium excited-state populations and the emission, attenuation, and scattering properties derived from them are tabulated for a variety of physical conditions appropriate to the -solar chromosphere (7500 < T < 50000 o K; 1010 < N e < 1012 cm-3) for some of the main spectral lines of hydrogen and CalI.

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The Double Reversal in the Cores of the Fraunhofer H and K Lines.

Cited by 33 publications

References 0 publications

A three-component model for the formation of the chromospheric Caii K line

A three-component model for the formation of the chromospheric Caii K line

Spectral analysis of sunspot flares

Excitation of Hydrogen and Ca II Under Chromospheric Conditions

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