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  • 1980-1984  (3)
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Material
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  • 1
    Electronic Resource
    Electronic Resource
    The chromosphere above a sunspot umbra (1982)
    Springer
    Solar physics 79 (1982), S. 31-39 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Spectra of several strong lines of sunspots have been obtained with the Echelle spectrograph at the Vacuum Tower Telescope, Sacramento Peak Observatory. With a variety of model atmospheres, Ca ii H, K, and λ18498 line profiles were calculated using a non-LTE line formation procedure. In the present study we examined only a specific part of the sunspot umbra which is thought to be coolest over the spot. An optimum model representing such a region is presented and its physical properties are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00146971
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Intensity ratios of spectral cores Ca ii K to H across a sunspot (1982)
    Springer
    Solar physics 78 (1982), S. 347-349 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Ratios of the intensity in the core of the Ca ii K line to the intensity of the H line core across a sunspot (SPO 5007) were determined from measurements of spectra made simultaneously with the Echelle spectrograph at the Vacuum Tower Telescope, Sacramento Peak Observatory. The measured values averaged over the neighboring nonspot region, the penumbra and the umbra are found to be 1.13 ± 0.04, 1.19 ± 0.05, and 1.25 ± 0.03, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151613
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A model of a penumbral chromosphere (1984)
    Springer
    Solar physics 92 (1984), S. 145-151 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A semi-empirical model of a penumbral chromosphere is presented which represents a specific region of the penumbra located approximately one-fourth the distance outward from the umbra-penumbra interface. The model is based on simultaneous observations of high-resolution spectra of Caii K, H, and λ8498 made over a sunspot penumbra (SPO 5007) with the Echelle Spectrograph at the Vacuum Tower Telescope at Sacramento Peak Observatory on 18 December, 1979. Spectral profiles were calculated using a non-LTE line formation procedure with various chromospheric models where the optimum model is determined by matching the synthesized profiles with the observational features. The best fit yields a model with overlying column mass m 0 of 8 × 10−6 g cm−2 which also agrees with the observed K3/H3 intensity ratio of 1.22.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00157241
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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