CY Aquarii

Kulikovsky, P.G. and კულიკოვსკი, პ. (1937) CY Aquarii. აბასთუმნის ასტროფიზიკური ობსერვატორიის ბიულეტენი / Bulletin of the Abastumani Astrophysical Observatory (1). pp. 47-53.


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The variability of the star BD+0°4900; 9^m.3 was discovered by Hoffmeister and Jensh at the Berlin Babelsberg Observatory. The star received the preliminary designation: 391.1934 Aquarii. The visual observations of this star showed its exceptionally short period—about 88 minutes. The star has been observed subsequently by Jensh, Hoffmeister, Detre and Balazz, Wachmann, Dawson, Selivanoff, Müller, Gaposhkin, Lause, Parenago, Rabkin and Lange. From the numerous visual and photographic observations the conclusion may be drawn that this star belongs to the short- period Cepheids (cluster type) and has the shortest period thus far known. The insufficient accuracy of the photographic curves published induced me to make new photographic observations. The photographic material was obtained in the Newtonian focus of the 13-inch reflector of Abastumani Observatory on "Fulgur" plates with exposures of 1, 1.5 and 2 minutes (the exposures being shorter at maximum). In accordance with the practice generally adopted at Abastumani Observatory, the photographs were taken slightly intrafocally with a view of their further measurement by means of the microphotometer. On August 31 and September 1 and 2, 1935, 205 exposures of CY Aquarii were obtained (Table I). To obtain the photographic magnitudes of the comparison stars two special plates of the KSA37 were taken. The magnitudes of the stars of this area were taken from the paper by Parkhurst and from HGD and reduced to the International Scale. The mean values arc given in Table II. Two independent comparisons with KSA37 gave the preliminary magnitudes of the comparison stars listed in Table III. For each plate the characteristic curve has been plotted. Ordinates are the galvanometric values (E); abscissae give the magnitudes. Each of the five points has as ordinate the mean reading for all images of the given comparison stars and has as abscissa the stellar magnitude of the same star (see Fig. 2, where the characteristic curve is drawn on the basis of measurements of plate No. 742). For each image of the variable star in the quantity E a correction for the individual difference of the given exposure from the mean was introduced. This correction was obtained as the mean value of deviations of E for all comparison stars from the characteristic curves. The brightness of the variable star at every exposure was read from the characteristic curve. The obtained observations are included in Table IV. In calculating the phases the initial epoch of Jensh and the period of Gaposhkin were used. Phases were calculated according to the formula (1). After reduction of all observations to a single period the following mean light-curve was obtained (Table V and Fig. 3). Each normal point represents 10 single observations. The mean error of each individual observation is ±0^m.08. The mean error of the normal points is ±0^m.026. The moment of maximum determined by Pogson’s method, deviates from the adopted elements by — 0^p.1014. The new value for the period determined by the author is: P=0^d.06103833.

Item Type: Article
Subjects: Q Science > QB Astronomy
Divisions: Institutes > Evgeny Kharadze Abastumani National Astrophysical Observatory
Depositing User: თამარ ჭაღიაშვილი
Date Deposited: 18 May 2018 12:27
Last Modified: 02 Jun 2018 18:14

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