Abstract
A detailed photometric comparison between a Mgii K filterheliogram and a nearly simultaneous Caii K spectroheliogram is presented. The comparison shows a close correspondence in both location and intensity of the bright features on the Sun with a correlation coefficient of 0.92 ± 0.02 between the Mgii and the Caii intensities in active regions.
A small flare is most likely observed in the Mgii heliogram giving a substantial contribution to the recorded intensity.
We also estimate theoretically the heights in the solar atmosphere at which the Mgii K and Caii K lines are formed. Taking into account the general shape of the line profiles and the different passbands used in the recordings we arrive at an average height of formation of 1700–1900 km above the photosphere for these particular heliograms.
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References
Athay, R. G.: 1970, private communication.
Athay, R. G. and Skumanich, A.: 1967, Ann. Astrophys. 30, 669.
Athay, R. G. and Skumanich, A.: 1968a, Solar Phys. 3, 181.
Athay, R. G. and Skumanich, A.: 1968b, Solar Phys. 4, 176.
Bates, B., Bradley, D. J., McKeith, C. D., McKeith, N. E., Burton, W. M., Paxton, H. J. B., Shenton, D. B., and Wilson, R.: 1969, Nature 224, 161.
Dumont, S.: 1967, Ann. Astrophys. 30, 421 and 30, 861.
Eddy, J. A., Lena, P. J., and MacQueen, R. M.: 1969, Solar Phys. 10, 342.
Engvold, O.: 1966, Astrophys. Norv. 10, 101.
Fredga, K.: 1969a, Appl. Optics 8, 333.
Fredga, K.: 1969b, Solar Phys. 9, 358.
Gingerich, O.: private communication August 1970 Gingerich, O., Noyes, W., Kalkofen, W., and Cuny, Y.: 1971, Solar Phys. 18, 347.
Gingerich, O. and de Jager, C.: 1968, Solar Phys. 3, 5.
Jefferies, J. T.: 1968, Spectral Line Formation, Blaisdell Publ. Comp., Waltham, Mass.
Jefferies, J. T. and Thomas, R. N.: 1959, Astrophys. J. 129, 401.
Jefferies, J. T. and Thomas, R. N.: 1960, Astrophys. J. 131, 695.
Lemaire, P.: 1969, Astrophys. Letters 3, 43.
Lemaire, P.: 1970, in L. Houziaux and H. E. Butler (eds.) Ultraviolet Stellar Spectra and Ground-Based Observations, IAU Symp. 36, 250.
Linsky, J. L.: 1968, Smithsoman Astrophys. Obs. Spec. Report 274.
Linsky, J. L.: 1970, Solar Phys. 11, 355.
Linsky, J. L. and Avrett, E. H.: 1970, Publ. Astron. Soc. Pacific 82, 169.
Parkinson, W. H. and Reeves, E. M.: 1969, Solar Phys. 10, 342.
Purcell, J. D., Garrett, D. L., and Tousey, R.: 1963, Space Research III (ed. by W. Priester), p. 781.
Thomas, R. N.: 1957, Astrophys. J. 125, 260.
White, O. R. and Suemoto, Z.: 1968, Solar Phys. 3, 523.
Zirker, J. B.: 1968, Solar Phys. 3, 164.
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Fredga, K. A comparison between Mgii and Caii spectroheliograms. Sol Phys 21, 60–81 (1971). https://doi.org/10.1007/BF00155775
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DOI: https://doi.org/10.1007/BF00155775