Abstract
The photometry of coronal colour negatives is carried out. The films were obtained at the March 7, 1970 and July 10, 1972 eclipses. A distribution of the coronal brightness in the red (635 nm), green (545 nm), and blue (455 nm) wavelength intervals up to distances of (6–7)R ⊙ is deduced (Figure 1). Colour indexes of the corona (the emission ratio red/blue - C rb and green/blue - C gb) have been obtained. We assume C rb = C gb = 1 in the inner corona (≤2R ⊙). The maximum of colour indexes of the 1970 corona are at the distances of about 4R ⊙ (C rb≤ 1.9 and C gb ≤ 1.7). A slight reddening within the limits of the errors was found in the 1972 corona.
There is a correlation between colour indexes and diffuse external reinforcements (RED) brightness. The analysis of the results leads to the conclusion that RED consists of dust grains with radii ≥1 μm. RED brightness is evaluated to be 4 × 10-10 B ⊙. There is 1 grain of dust in the elementary volume with cross section of 1 cm2 along the line of sight. The intensity of dust emission in wavelength interval 10 μm deduced by the authors is approximately 1 μW cm-2 s m−1. That is in agreement with Mankin et al. (1974) and Léna et al. (1974) observations. The whole dust mass of RED is ≤1% of the coronal gas mass contained within RED region. The dust grain number density is about 10-11 cm-3.
Determinations of the colour of the solar corona have been made by a number of scientists (Tikhov, 1940, 1957; Allen, 1946; Blackwell, 1952; Michard, 1956; Sharonov, 1958; Nay et al., 1961). The corona colour was found to be somewhat redder than the Sun's. However this question is not finally settled to date.
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References
Allen, C. W.: 1946: Monthly Notices Roy. Astron. Soc. 106, 137.
Blackwell, D. E.: 1952, Monthly Notices Roy. Astron. Soc. 112, 652.
Grotrian, W.: 1934, Z. Astrophys. 8, 24.
Hata, S. and Tojo, A.: 1972, Ann. Tokyo Astron. Obs. 13, 149.
Högner, V.: 1969, Jener Rundschau 14, 340.
Koutchmy, O. and Koutchmy, S.: 1974, Astron. Astrophys. Suppl. Series 13, 295.
Koutchmy, S.: 1972, Astron. Astrophys. 16, 103.
Koutchmy, S. and Nikolsky, G. M.: 1973, Institute d'Astrophysique, Paris (preprint).
Kouchmy, S., Dzubenko, N. I., Nesmjanovich, A. T., and Vsekhsvjatsky, S. K.: 1974, Solar Phys. 35, 369.
Lamy, Ph.: 1974a, Astron. Astrophys. 33, 191.
Lamy, Ph.: 1974b, Astron. Astrophys. 35, 197.
Lamy, Ph.: 1976, Lecture Notes Physics 48, 437.
Léna, P., Viala, Y., Hall, D., and Soufflot, A.: 1974, Astron. Astrophys. 37, 81.
MacQueen, R. M.: 1968, Astrophys. J. 154, 1059.
Mankin, W. G., MacQueen, R. M., and Lee, R. H.: 1974, Astron. Astrophys. 31, 17.
Michard, R.: 1956, Ann. Astrophys. 19, 229.
Ney, E. P., Huch, W. F., Kellog, P. J., Stein, W., and Gillet, F.: 1961, Astrophys. J. 133, 616.
Peterson, A. W.: 1963, Astrophys. J. 138, 1218.
Peterson, A. W.: 1967, Astrophys. J. Letters 148, L37.
Sharonov, V. V.: 1958, Total Solar Eclipses of 25 February 1952 and 30 June 1954, Acad. Sci. USSR, Moscow, p. 199 (in Russian). Tikhov, G. A.: 1957, General Works, Vol. 3, Acad. Sci. Kasakh. SSR, Alma-Ata (in Russian).
Tikhov, G. A.: 1940, Circ. of Pulkovo Obs., No. 28, p. 59.
Wickramasinghe, N. C.: 1973, Light Scattering Functions for Small Particles with Applications in Astronomy, Hilger, London.
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Ajmanov, A.K., Nikolsky, G.M. The colour of the solar corona and dust grains in it. Sol Phys 65, 171–179 (1980). https://doi.org/10.1007/BF00151391
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DOI: https://doi.org/10.1007/BF00151391