Publications
Section: PZ: main journal
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We performed the O-C analysis of period variations of the ultracompact binary system ZTF J213056.71+442046.5, a potentially detectable source of mHz gravitational waves for planned space laser interferometers. We combined our photometric observations carried out at the RC600 telescope of the Caucasus Mountain Observatory with publicly available ZTF survey data, thus increasing to 5.5 years the time interval covered with measurements. The O-C diagram is well fitted with linear light elements (P=0.0273195154 days) but can be also described with quadratic light elements corresponding to a period decrease rate of dP/dt = (-2.00 +/- 0.60) x 10^{-12} s per second. This finding is in a good agreement with the predicted value of the orbital period decay of this binary system due to gravitational wave emission.
We present a new Name-List of variable stars containing information on 1077 stars of the whole sky (constellations Andromeda - Vulpecula) recently designated in the system of the General Catalogue of Variable Stars (GCVS). Among variable stars of the Name-list, there are nine Novae of our Galaxy, named in the GCVS system soon after their discovery upon request from the Central Bureau of Astronomical Telegrams.
In 2005 - 2014, we obtained 16568 photometric measurements in the BVIc photometric system for 64 type II Cepheids and 54 RV Tau stars using the 76-cm telescope of the South African Astronomical Observatory (SAAO, South Africa) and the 40-cm telescope of the Cerro Armazones Observatory of the Universidad Catolica del Norte (OCA, Chile). The tables of observations and the plots of light curves are presented.
I present a catalog of newly detected Multi-Mode Radially Pulsating (MMRP) variable stars that pulsate in the fundamental, first, second, or third-overtone modes. This catalog includes 50 double- and multi-mode stars. Among variability types of these stars, we find classical Cepheids, RR Lyrae, and high-amplitude δ Scuti (HADS) variables. Additionally, I studied 14 known multi-periodic variables. I analyzed all observations available for these stars in the ASAS-SN and ZTF online public archives using the period-search software developed by Dr. V.P. Goranskij for Windows environment. Light elements and parameters of oscillations were determined.
About 600 CCD magnitude measurements in the g', r' filters were acquired in 2022 for four long-period eclipsing binaries: V698 Cyg, V788 Cyg, EU Gem, V733 Per. The light elements for all these systems were derived using the ASAS-SN database.
We performed timing of eclipses of the binary system V359 Her and found evidence in favor of the existence of light-time effect in the system. It can indicate the presence of a third body with the lower limit of mass ~0.5 M_Sun, its orbital period being about 24 yr. We also estimated the rate of mass transfer between the components as 0.5 x 10^{-8} - 1.5 x 10^{-7} M_Sun per year. For this purpose, we used times of minima from literature, from our observations, and from light curves obtained by the TESS satellite.
Photometric observations of SN 2019tua, spanning 350 days of its evolution, show a linear light curve with a rate of brightness decline slower than for most SNe II-L. The maximum absolute magnitude of SN 2019tua, M_R=-18.0 mag, is close to the mean value for SNe II-L. SN 2019tua is the second type II SN in a dwarf galaxy UGC 11860. The two SNe were discovered with interval of 5 years, while the mean outburst SN frequency in such galaxies is about 1 event in 1300 years.
I present my discovery and CCD observations of two new small-amplitude delta Scuti (DSCTC) stars that demonstrate multiperiodic pulsations. The paper contains detected frequencies, light curves, finding charts, and other relevant information.
I present my discovery and CCD observations of three new small-amplitude delta Scuti (DSCTC) stars. Two of them demonstrate multiperiodic pulsations. The paper contains detected frequencies, light curves, finding charts, and other relevant information.
I present a detection of 14 new eclipsing white-dwarf plus main-sequence binaries. The light curves in different photometric bands are characterized by different values of the amplitude of the eclipsing minimum, it is the largest in blue light (g band), significantly smaller in red light (r band), while the eclipse in infrared light (i band) is not detected. Outside eclipses, a double wave is observed, characteristic of ellipsoidal variability. I analyzed all observations available for these stars in the ZTF and Catalina online public archives. Light elements and parameters of the light curves were obtained. Additionally, I studied two short-period eclipsing binaries, possibly of cataclysmic nature. |
