Publications
Section: PZ: main journal
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We report the results of our CCD photometry of several variable stars. As a result, we are able to confirm that four stars from the ZTF survey that were classified uncertainly are indeed high-amplitude delta Scuti stars. Periods, epochs of maximum light, magnitudes at maximum and minimum, phased light curves are presented.
We presents the results of our 13-year (2009 - 2022) photometric study of the young variable star V645 Cyg, which is a Herbig Ae/Be object located in a region of active star formation. Observations were carried out in the optical part of the spectrum, in VRI filters. During the observation time interval, we found, along with short-term small-amplitude chaotic brightness changes of V645 Cyg, we found a monotonous increase in the total brightness of the system in the V band by ~1 mag; in R, by ~1.4 mag; and in I, by ~2 mag, as well as an increase in the reddening of the system: its V-R color index increased by ~0.3 mag, and R-I, by ~0.6 mag. Optical brightness variations in the time interval JD 2450000 - 2456500 are closely followed by variations of the CH_3OH maser flux at 6.7 GHz reported in the literature. Absence of strong variations on the time scale of hours suggests that non-stationarity effects in the maser radiation are not significant. The monotonous changes in the brightness and color of V645 Cyg are interpreted as a decrease in the optical depth of the gas-dust cocoon towards the star and corresponding increase in the visibility of regions of the star and its immediate vicinity.
We present a set of light curves of the eclipsing binary system AS Cam that were used for studies of its apsidal motion rate and light equation. This system was considered unusual during several decades, because its apsidal motion rate was estimated from observations as very slow in comparison with the theory. The presented light curves can be used for independent studies.
We present the results of BVRcIc CCD photometric observations of the classical T Tauri stars AS 205 (V866 Sco), V1082 Cyg and the HAeBe star AS 310 obtained in 2016-2022. Photometric variations of the star AS 310 with a large amplitude were reliably established for the first time, they are possibly due to binarity or multiplicity of the star. The scale of the star's activity differs from a year to year. Parameters of the upgraded photometric system, currently at use at the Shamahy Observatory, are described.
CCD UBVRI photometry is presented for SN 2020mmz spanning 170 days of evolution. The dates and magnitudes of maximum light in different photometric bands and the parameters of the light curves are determined. The maximum luminosity and general behavior of the light curves are typical of the class SN II-L; the peculiar feature of SN 2020mmz is the fast brightness decline for the first 20 days after maximum.
I present my detection of a new triple-mode Classical Cepheid, pulsating in the fundamental mode, first- and second-overtone modes. I analyzed all observations available for the star 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 the light curves for the three oscillations were obtained.
The analysis of minima timings of the newly discovered W UMa variable GSC 3937 2349 (V=13.2m, P=0.2875d) revealed the light time effect that can be assigned to the third body in the system. Parameters of the third body orbit were derived and its mass was estimated, which turned out to be comparable to the mass of the components of the eclipsing system.
I present a detection of 44 new double-mode high-amplitude delta Scuti variable stars, HADS(B) type, pulsating in the fundamental and first overtone modes. We analyzed all observations available for these stars in the ASAS-SN online public archive using the period-search software developed by Dr. V.P. Goranskij for Windows environment. Additionally, in individual cases, I used data of the SuperWASP, CSS, and ASAS-3 surveys. Light elements and parameters of the light curves of both oscillations were obtained.
We obtained several light curves of V957 Cep in 2009, 2011, 2013, 2016, and 2019 at the Crimean Astronomical Station of M.V. Lomonosov Moscow State University and at the Tien Shan Observatory of the V.G. Fesenkov Astrophysical Institute. Using the TESS satellite observations, we found brightness variations of V957 Cep with the period P_p=0.664 d and amplitude A_p=0.0076 mag. For our light curves (2009-2019) and TESS light curves (2019-2020), orbital elements were computed and a new value of the apsidal motion rate d(omega)/dt=1.47 deg +/- 0.15 deg per year was derived. We found a possible light-time effect that can indicate gravitational influence of one or several additional bodies in the system on the central binary. Based on the currently available data, the amplitude and period of the light-time effect still cannot be reliably estimated.
We present calculations of radial velocity corrections along the phase curve due to influence of the spotted surface of the active giant, PZ Mon. The maximum deviation from a relatively uniformly-bright stellar disk is about 0.20 - 0.25 km/s. |
