Publications
Section: PZ: main journal
|
In September, 2021, we obtained about 1100 UBVRcIc CCD observations of the dwarf nova with coordinates RA=23h11m10.9s; Dec=+01deg30'03" (J2000) during its outburst. Our analysis of this photometric series showed that the studied variable star had superhumps at stage "B"; two rebrightenings were detected after the end of the outburst. The mass component ratio q = 0.06 was estimated; color temperature variations during the outburst were studied. The variable is a typical WZ Sge star with a short superhump period, 0.0516days. The detected period is close to the lower limit for the WZ Sge variables.
We present the results of long-term photometry (2009-2021) of the new W UMa-type star GSC 3599-2569 discovered in 2013 at the Kourovka Observatory. We have found a change in the period of this eclipsing system. Based on more extensive observational data, the previously detected cyclical change in the brightness of the system, not associated with eclipses and caused by spot activity on the surface of the components, was confirmed. The length of this period has been specified. 11 new times of minima of GSC~3599-2569 are presented.
An analysis of the new UBVR_cI_c observations of V1674 Her obtained by the authors shows that the star is a very fast Nova, with parameters T_2 = 1.1d, T_3 = 2.2d. The orbital period at the brightness decline, 39 - 56 days after the outburst, was 0.15290d, the shape of the light curve featured two unequal minima separated by half a period, the amplitude of the observed wave being 0.12 mag.
8001 magnitude measurements in the B, V, and I_c filters were acquired for the high-amplitude delta Scuti variable V2455 Cyg. The observations and light curves are presented.
1665 magnitude measurements in the B, V, g', and r' filters were acquired for the double-mode Cepheid AS Cas. The light curves for both fundamental and first-overtone modes were constructed.
I present a detection of a new double-mode type~II Cepheid (BL Her type), USNO-B1.0 0992-0344981, pulsating in the fundamental and first-overtone modes. It is the fifth case in the Galaxy of stars of this type. For the analysis, I used all observations available for the star in the ASAS-SN, ASAS-3, NSVS, and ZTF online public archives. Light elements and parameters of the light curves were obtained.
I present a study of two variable stars, GSC 08977-08895 and GSC 07418-01521. This study is a part of our search for double-mode and multi-mode periodicity of variables. GSC 08977-08895 shows variability of a Doubly Eclipsing System, type ELL+EA. GSC 07418-01521 is a high-amplitude double-mode Delta Scuti variable, pulsating in the fundamental and first overtone modes, with an eclipsing component, type HADS(B)+EA. Our photometric study of both stars is based mainly on ASAS-SN data. Additionally, for the first star, we used ASAS-3 data, for the second star, we used 1SWASP and SSS data. The light elements of all periodic variations of both variables and the parameters of their light curves were obtained.
We report photometry of two optical transients, MASTER OT J224524.92+211742.0 = AT2020ray and MASTER OT J213908.79+161240.2 = 2020ugj. Additionally, a spectrum of AT2020ray was obtained with the Russian 6-meter telescope, BTA. Both transients were classified as WZ Sge-type cataclysmic variables in superoutbursts. The superoutburst of AT2020ray was accompanied by multiple type B rebrightenings. In the bright state, both objects had strong UV excess.
We introduce a correction to the recent 83rd Name-list of Variable Stars.
We present our detection of 6 new Classical Cepheids and a photometric study of 7 known Classical Cepheids. We used all observations available for these stars in the ASAS-SN, 1SWASP, ASAS-3, and NSVS online public archives, our photographic estimates (for 6 stars) and our CCD observations (for 2 stars). We analyzed all data using the period-search software developed by Dr. V.P. Goranskij for Windows environment. Light elements and parameters of the light curves were obtained. |
