Vashakidze, M.A. და ვაშაკიძე, მ. (1943) An Investigation of the Polarization of the Solar Corona at the Total Eclipse on September 21, 1941 / მზის კორონის პოლარიზაციის გამოკვლევა 1941 წლის 21 სექტემბრის მზის სრული დაბნელების დაკვირვების საფუძველზე. აბასთუმნის ასტროფიზიკური ობსერვატორიის ბიულეტენი / Bulletin of the Abastumani Astrophysical Observatory (7). С. 1-31.
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The present paper deals with the results of the investigation of the polarization of the solar Corona observed at the total eclipse on the 21 of September, 1941. The data of the observation were obtained by the expedition of the Abastumani Observatory sent to Kazakh Soviet Socialist Republic together with the expeditions of Leningrad Astronomical Institute and Kazan Engelhardt Observatory. The village Djalanash of Alma-Ata district was chosen as the location of our expedition where pavilions for observational instruments were built beforehand. Our task was to study the degree and the direction of the polarization of the outer Corona in photographic and visual rays. The study of the polarization of the solar Corona enables us chiefly to investigate the physical nature of the Corona and to find out what particles cause the scattering of the sunlight in the Corona, in particular. If the scattering of light is made by free electrons, then the degree of the polarization must not depend upon the wavelength, as it follows from Thomson's formula. But Cohn, Zakharin and others acknowledge in a number of works that the polarization of the Corona rather clearly depends upon the wavelength. At the same time Dufay and Grouiller showed that the polarization is independent of the wavelength. From the works mentioned above it is seen that the degree of polarization is changed depending upon the distance from the Sun's limb and upon the position angle. But these dependence obtained by different observers were not alike. This shows that it is necessary to perform the observations and to work up the observational material obtained extremely carefully. There is no doubt that reliable data of observations can answer the question what particles cause the scattering of the sunlight in the Corona. Probably the scattering of light is caused both by electrons and by dusty particles. Besides, as supposed Young, there exists radiation of the Corona itself, we have on the whole partly polarized light mixed with the natural one. In the summary of our paper we shall come back to the question the physical nature of the Corona, using the results of our observations. In conclusion we can say that the polarization in the inner Corona is a little greater for photographic rays, than that for visual ones. But in the outer Corona their values come nearer and become almost identical. Generally speaking, having in view our remarks about the accounting of the background, we are inclined to consider the polarization not to be dependent upon the wave-length. The maximum degree of polarization is at the distance from 4' to 12 from the Sun's limb (it is possible that the interval is wider). It is in this interval that takes place the deviation of the maximum of polarization depending upon the position angle. The value of the degree of polarization is changed both according to the position angle and along the radius itself. The polarization according to the position angle and along the radius is changed so much that it is difficult to compare the results of many writers who observed various eclipses and took different parts of the Corona both according to the position angles and along the radii. So no wonder that the insignificant values of polarization degree were obtained by Dufay and Grouiller. If to examine our Table II it is easy to see that on some radii, for instance, φ = 75°, φ = 240°, the degree of polarization is less, than those of Dufay and Grouiller, but for φ = 132° the value is obtained the same as that of Cohn. So the existing theories of the polarization of the Corona relating to the polarization of the entire Corona must be considered to be of a very rough approaching to the reality. Both the radii indicated above, and the radii φ = 48°, φ = 225°, φ = 228° and others display very small value of polarization in these parts of the Corona, i. e. it turns out that there are such regions in the Corona where the per cent of polarized light is very insignificant and therefore it is pοssible that mainly the radiation of the Sun itself takes place. The opinion, existing up to the present time that the plane of polarization is radial, should be considered to be proved, but for the outer Corona the investigation of this problem becomes intensely complicated due to difficulty of accounting of the background of the sky and atmospheric polarization. In the computations of the degTee and the direction of polariiation we did not take into account the displacement of the Moon's disc during totality. But it should be accounted, if the expositions of three succeeding photographs are more or equal to 15 sec each. Our expositions were not so long. As far as we know the indicated displacement was not taken into account by all other previous investigators. This fact must be considered to be the general drawback of the previous investigations. At last l should like to express my sincere gratitude to computers T. Megrelishvili, X. Kalandadse, E. Dolidse and E. Brodskaja, who have done almost all work On measurements and computations. December, 1942
| ობიექტის ტიპი: | სტატია |
|---|---|
| თემატიკა: | Q Science > QB Astronomy |
| ქვეგანყოფილება: | Institutes > Evgeny Kharadze Abastumani National Astrophysical Observatory |
| განმათავსებელი მომხმარებელი: | თამარ ჭაღიაშვილი |
| განთავსების თარიღი: | 25 მაისი 2018 10:10 |
| ბოლო ცვლილება: | 25 მაისი 2018 10:10 |
| URI: | http://eprints.iliauni.edu.ge/id/eprint/7998 |
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