Difference in the value of Color - excess for the clusters h and χ Persei / Разность колор эксцессов скоплений h и χ Persei

Dombrovskaya, A.M. and Домбровская, А.М. (1940) Difference in the value of Color - excess for the clusters h and χ Persei / Разность колор эксцессов скоплений h и χ Persei. აბასთუმნის ასტროფიზიკური ობსერვატორიის ბიულეტენი / Bulletin of the Abastumani Astrophysical Observatory (4). pp. 69-76.


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The investigations of a number of authors have shown a considerable reddening of the stars in the double cluster h and x Persei. It is very interesting to investigate the color-excess of one cluster as compared with that of the other. As the distances between us and the clusters h and x Persei are about the same, a relative reddening can only be caused by the inequality in the distribution of the inter-stellar, absorbing matter. This question is discussed in the preseut work. The method of spectrophotometry gradients has been adopted. As we arc only interested in the comparative color-excess, all the gradients are given in relation to a free-chosen zero-point and are not reduced to the known Greenwich system of gradients. This investigation is based on three spectrograms obtained at the A b a-s t u m a n i Observatory by means of an 8-inch camera (object-glass No 2, focal length = 1 meter) and an objective prism, having the angle of refraction equal to 5. 30', linear dispersion being 3 mm from Hs to Hβ. The spectrograms were taken on the Astra IX plates* The B and A type stars situatrd near the centers of the clusters were taken for present investigation. The difference obtained between the mean values of the reduced gradients for thε clusters h and χ is equal to 0.21. Fig. 1 shows the correlation between our gradients and those of T h o r nd i k e . Fig. 2 represents the dependence of the gradients obtained upon the spcctral class. The gradients obtained were plotted on the map of h and / Persei clusters with the purpose of a detailed investigation of the distribution of the absorbing matter^filling the inter-stellar space (Fig. 3). It has appeared impossible, however, to notice any regularity in the distribution of the gradients. In Fig. 4 the dependence of the obtained gradients on the apparent magnitude b shown. 1 he gradients increase as we pass from the bright stars to the faint ones. June, 1939

Item Type: Article
Subjects: Q Science > QB Astronomy
Divisions: Institutes > Evgeny Kharadze Abastumani National Astrophysical Observatory
Depositing User: თამარ ჭაღიაშვილი
Date Deposited: 11 Jul 2018 09:59
Last Modified: 11 Jul 2018 09:59
URI: http://eprints.iliauni.edu.ge/id/eprint/8188

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