Колор-индексы 4535 звёзд в одиннадцати площадках Kapteyn'а / Color-indices of 4535 Stars in Eleven Kapteyn Areas

Kharadze, E.K. და ხარაძე, ე.კ. და Харадзе, Е.К. (1943) Колор-индексы 4535 звёзд в одиннадцати площадках Kapteyn'а / Color-indices of 4535 Stars in Eleven Kapteyn Areas. აბასთუმნის ასტროფიზიკური ობსერვატორიის ბიულეტენი / Bulletin of the Abastumani Astrophysical Observatory (7). С. 99-188.

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In our previous article we informed readers of the work undertaken by us on determination of color-indices of stars between 11^m.0-13^m.0 in Kapteyn Selected Areas. The article treated mainly of methodical aspect and contained the list of color-indices of 1758 stars in five KSA of the galactic equator. The present paper, being in fact the continuation of the previous one, contains the determination of color-indices of 4555 stars more: This number of stars together with the first list makes one third part of the Catalogue planned for the nearest years to come. In this article we consider the questions of methodics and the accuracy of our determinations and at the same time, using rather considerable material (6293 stars in sixteen KSA), we try to obtain some preliminary conclusions relating to distribution and the character of absorbing medium. The KSA inserted in the present paper are listed in Table I. The negatives used for our determinations are described in I able II. For each Area it was used from 3 to 6 pair of negatives and each pair was measured at least twice. The exposure time was alternated from 10 to 60 minutes. The effect of a difference of stellar images on photographs of KSA and NPS, called forth by the impossibility to control the work of a driving mechanism, presents the main source of errors in our determinations. In connection with this for some time past we began to shorten the exposure time for plates in photographic rays, where this effect was manifested especially sharply. We used the same light-filters BG, and GG. The regime of taking photograph* and developing of plates remained the same. The correction of color-indices for the atmospheric extinction usually did not exceed two or three hundredth of a stellar magnitude. Comparing these data with some well known, one should name Zug who investigated the region near the direction to KSA 8 and found Apg to be equal to o" 9 and Bok who found Apg to be equal to 1-2 in the same direction. Besides, Bok indicates that in this direction the absorption rapidly increases m the direct proportion to the distance up to 2400 ps. The agreiment is here almost full notwithstanding that the stars of our list are distributed by chance round the centre of KSA on the area with a known radius. Bok determined the colours of stars distributed in regions of KSA with even background displaying at the same time the least obscuration. It will be just to the purpose to note here that in spite of known independence of final results upon some arbitrariness in the choice of stars in KSA in mass determinations, it is expedient to investigate separately small parts of Kapteyn areas. KSA 9 is located in more homogeneous region. Here our value of general photographic absorption is less than that of Bok but approximates to the data of Stebbins and Huffer. But this accordance should not be considered as quite reliable, as far as the mentioned authors were dealing with the distances not exceeding 500 ps while our distances reach 2500 ps. The increase of absorption with the growth of a distance up to 1600 ps. also characteristic for KSA is which is in the neighbourhood of some obscured regions. We shall mention here once more that the results stated here may be regarded only as preliminary but even in such an appearance they lead us to interesting conclusions and, principally, indicate that the completion of work on the determination of color-indices of large number of stars promises us to give new and reliable results. Our immediate tasks are the precise determination of the effective wavelengths of our system, the foundation of a system of normal colours and making more accurate all reductions and in the first place the equations connecting our color-indices with the international ones- As to the further collecting of the material we intend to give the list of color-indices of stars in KSA within the roue of b=±10- 20c and besides, to widen our published lists of the zone b=±0—10c with supplementary stars which had been measured but had not been for some reasons included in the lists. The discussion of the material must also include the question about the law of the dependence upon the wave-length. At last the data of our work must be connected with known results of detailed investigation of some clouds of absorbing matter, particularly, with minute investigations of regions of Auriga, Cygnus and others where our KSA are located. April, 1943

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 10:09
ბოლო ცვლილება: 25 მაისი 2018 10:09
URI: http://eprints.iliauni.edu.ge/id/eprint/8001

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