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  • 1970-1974  (23)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    One- and multi-component models of the upper photosphere based on molecular spectra (1974)
    Springer
    Solar physics 35 (1974), S. 259-276 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have obtained center-to-limb photoelectric spectra of the CN(1,1) B-X bandhead region λ3868–3872 Å at Kitt Peak National Observatory. From these spectra and a detailed analysis of the formation of the CN (1, 1) spectrum we derive a best-fit upper photospheric model differing from the HSRA which is consistent with our previous CN(0, 0) λ3883 spectra. We derive a solar carbon abundance of log A c = 8.30 ± 0.10 compared to the HSRA value of log A c = 8.55 ± 0.10. In addition we specify the regions of formation for the CN(0, 0) λ3883.35 and CN(1, 1) λ 3871.38 bandheads at disc center and limb.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151947
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  • 2
    Electronic Resource
    Electronic Resource
    One- and multi-component models of the upper photosphere based on molecular spectra (1974)
    Springer
    Solar physics 36 (1974), S. 287-298 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have obtained accurate center-to-limb photoelectric spectra of the CH (0, 0) C-X bandhead region λ3143–3148 Å at Kitt Peak National Observatory. From these spectra and a detailed analysis of the formation of the CH (0, 0) spectrum we demonstrate that the best-fit upper photospheric model derived from our previous analyses of CN (0, 0) and CN (1, 1) spectra adequately explains the CH C-X observations. In addition we derive a solar carbon abundance of ±0.20 compared to the HSRA value of log Ac = 8.55. This confirms our previous CN analyses which demonstrated that if the HSRA nitrogen abundance of log AN = 7.93 ± 0.10 is assumed, then log Ac = 8.20 ± 0.10. We also specify the regions of formation for the CH(0, 0) λ3143.47 Å band-head at disc center and limb.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151197
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  • 3
    Electronic Resource
    Electronic Resource
    A facular model based on the wings of the Ca ii lines (1974)
    Springer
    Solar physics 37 (1974), S. 145-150 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We develop a relatively simple procedure for deriving models of upper photospheric regions based on the damping wings of the Ca ii resonance and infrared triplet lines. The procedure is used to derive a facular model but can also be applied to late-type stars. We compare our model to that of Chapman.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00157850
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  • 4
    Electronic Resource
    Electronic Resource
    Physical properties of solar chromospheric plages (1972)
    Springer
    Solar physics 25 (1972), S. 357-379 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Double pass photoelectric observations are presented of five Caii lines (H, K, 8498 Å, 8542 Å, and 8662 Å) in a number of solar plages of different degrees of activity, quiet regions, and a sunspot. The data are compared with previous work. All five lines show increasing emission together in plages and the least opaque of the infrared triplet lines appears to exhibit core emission prior to the more opaque members of the multiplet. The question of source function equality is considered and the differences and similarities among plage profiles and between plage and quiet profiles are shown qualitatively and quantitatively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192335
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  • 5
    Electronic Resource
    Electronic Resource
    A recalibration of the quiet Sun millimeter spectrum based on the Moon as an absolute radiometric standard (1973)
    Springer
    Solar physics 28 (1973), S. 409-418 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The solar millimeter continuum between 1 and 20 mm is recalibrated using observations of the average lunar brightness temperature at the center of lunar disk and new Moon brightness temperatures. The solar data are placed on a common scale according to the average lunar brightness temperature distribution proposed by Linsky. A least-squares parabolic regression curve is proposed for the solar millimeter continuum. A small departure from this regression curve near 8 mm may indicate the existence of an absorption feature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152312
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  • 6
    Electronic Resource
    Electronic Resource
    One- and multi-component models of the upper photosphere based on molecular spectra (1973)
    Springer
    Solar physics 32 (1973), S. 13-30 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Spectroheliograms taken in the CN(0, 0) violet band near λ 3883 Å show very small scale network and cell structures with high contrast. The bandhead itself, which is a broad feature due to overlap of several CN lines, allows the diagnostic simplicity of a continuum since motions, magnetic fields, and broadening mechanisms are unimportant. We have obtained spectroheliograms in the bandhead and center-to-limb photoelectric spectra of CN(0, 0) at Kitt Peak National Observatory. From the photoelectric spectra and a detailed analysis of the formation of the CN(0, 0) spectrum we derive a best-fit one-component upper photospheric model differing from that of the HSRA and recommend a change in solar carbon abundance from the HSRA value of logA c = 8.55 to logA c = 8.25. From the calibrated spectroheliograms we consider a multi-component model to account for the observed fine structure intensity variations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152726
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  • 7
    Electronic Resource
    Electronic Resource
    Can the ion H3 + account for missing opacity in the solar ultraviolet? (1970)
    Springer
    Solar physics 11 (1970), S. 198-207 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Limb darkening and specific intensity data imply more continuous opacity in the solar photosphere between 2000 Å and 3500 Å than has been predicted theoretically. The temperature dependence and wavelength dependence of this missing opacity are in qualitative agreement with those deduced for the ion H3 +, but it is unlikely that H3 + is sufficiently abundant to account for this opacity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00155220
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  • 8
    Electronic Resource
    Electronic Resource
    On the relative residual intensities of the calcium H and K lines (1970)
    Springer
    Solar physics 11 (1970), S. 355-373 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have observed the solar Caii H and K lines to obtain well-calibrated ratios of their core residual intensities. From three independent calibrations, one using a standard lamp, we conclude that the residual intensity ratio r(K3)/r(H3) is 1.048 ± 0.03 in the quiet chromosphere and 1.20 ± 0.03 in a plage region. These ratios correspond closely to those observed in stars with quiet and active chromospheres, respectively. For a chromospheric model suggested by the calcium lines and a four-level Caii ion, we compute H and K line profiles varying the direct collisional coupling and indirect radiative and collisional coupling via the 3 2 D level. We conclude that enhanced chromospheric activity in the sun and late-type stars results more from a steepening of the chromospheric thermal gradient than from a change in density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00153071
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  • 9
    Electronic Resource
    Electronic Resource
    Observations of the infrared triplet of singly ionized calcium (1970)
    Springer
    Solar physics 11 (1970), S. 374-383 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Observations are presented of the Caii infrared triplet (8498 Å, 8542 Å, and 8662 Å) at three positions on the solar disk to make possible direct analyses of the lines and comparisons with theoretical computations. The source functions for the two strongest lines (8542 Å and 8662 Å) are equal at those heights corresponding to the wings of the lines (¦Δλ¦ 〉 0.4 Å) but not to those of the cores. We suggest that the apparent source function inequality in the cores is due to limb darkening caused by inhomogeneities in the chromosphere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00153072
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  • 10
    Electronic Resource
    Electronic Resource
    Physical properties of solar chromospheric plages (1974)
    Springer
    Solar physics 39 (1974), S. 49-77 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We propose chromospheric models of plages to explain profiles of the Ca ii H, K, λl8498, λ8542, and λ8662 lines described in Paper I. These models are consistent with boundary conditions imposed by the photosphere and the Lyman continuum. We find that increasing emission in these lines is consistent with a picture of increasing temperature gradient in the low chromosphere and the resulting increase in pressure and electron density at similar line optical depths. With this picture we suggest how to empirically determine the distribution of chromospheric parameters across the solar disk directly from Ca ii filtergrams. We also propose that the high density aspects of solar activity are produced by steep temperature gradients in the low chromosphere and thus by the enhanced heating mechanisms that steepen these gradients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00154970
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