Publications
Section: PZ: main journal
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High precision photometric observations of the bright Nova V1112 Per at early stages after its outburst are presented. We found the time of the star's maximum brightness, estimated its interstellar extinction using empirical formulas. Our data made it possible to determine the mass of white dwarf M_(wd) = 0.82+/-0.07 M_(Sun) and the distance to the star d = 5.2 +/- 0.4 kpc. Fast variability at early stages was detected.
Six binary and candidate binary stars in the fields of V0873 Per and CV Boo were found using archive observations of the Mt.~Maidanak Astronomical Observatory. (1) 2MASS J02465266+4125290 is a detached eclipsing binary with the period of P=5.9436+/-0.0027 d. (2) TYC 2853-60-1 is a detached eclipsing binary with the period of P=1.79+/-0.01 d. (3) 2MASS J02475840+4116103 is an ellipsoidal binary system with the period of P=0.30744+/-0.00005 d. (4) 2MASS J02464361+4120282 is a BY Dra-type binary star with the rotational period of P=12.18+/-0.06 d. (5) 2MASS J02465622+4117392 is an ellipsoidal binary system with the period of P=4.022+/-0.009 d. (6) 2MASS J15273711+3703070 is an ellipsoidal and/or RS CVn binary system with the period of P=0.3307+/-0.0002 d. Three of these stars exhibit chromospheric activity.
We derive RR Lyrae period - metallicity - mid-infrared
luminosity relations in the WISE W1 and W2 bands based on
intensity-mean W1 and W2 magnitudes computed from
intensity-mean Gaia G_(BP) and G_(RP) magnitudes and known
metallicity [Fe/H] for ~5000 field RR~Lyrae variables and
~700 variables in 24 globular clusters:
The recent Gaia DR3 all-sky list of candidates for eclipsing binaries including 2,184,477 sources, and the list of probable members of galactic clusters by Hunt and Reffert (2024), are used to identify eclipsing binary stars -- members of star clusters, and to compare their general characteristics to those of eclipsing binaries in the galactic field. We find that the distributions over orbital frequencies notably differ from each other due to dynamic evolution of binary star orbits in galactic clusters. On the other hand, the distributions over the depth ratio of minima in clusters and in galactic field are similar, which supports the universality of pairing algorithm during binary star formation.
Photometric observations of SNe 2012ch and 2012fs show light curves characteristic of type II-P Supernovae. The interstellar extinction for both SNe was estimated by comparison of their color curves with those for well-studied SNe II-P. The absolute magnitudes at the plateau stage are M_R=-17.1 for SN 2012ch and M_R=-16.9 for SN 2012fs, which is close to mean values for the objects of this class. We performed modeling of the light curves of SN 2012ch with the STELLA code, the optimal model has the following parameters: total mass 19M(Sun), radius 900R(Sun), explosion energy 1.5 x 10^(51) erg, mass of (56)Ni 0.07M(Sun).
We estimated the apsidal motion rate in the eclipsing binary system V1437 Cas using TESS light curves d(omega)/dt=0.252+/-0.025 deg/yr. Existing TESS light curves of the system contain 4 extremely deep minima of unknown nature.
In January 1924, Ejnar Hertzsprung discovered a new variable star, DH Car. As it later turned out, this was the first discovery of a flaring red dwarf, type UV Cet in current classification. I present the first determination of the rotation period of DH Car from data acquired with TESS orbital observatory. The period is 0.89 days.
We present photometric BVRI observations of type II SN 2019osl covering 177 days. We determine the dates and magnitudes at maximum light and estimate interstellar extinction by comparison of its color curves with that for a sample of SNe II. The maximum absolute magnitude M_V = -17.9 mag is about 1.2 mag brighter than the mean value for SNe II. The host galaxy UGC 3115 is classified as a lenticular galaxy, but we show that this classification is erroneous, because the images of the galaxy from Pan-STARRS survey clearly reveal a spiral structure.
We present a new Name-List of variable stars containing information on 1610 variable stars in 31 globular star clusters, in four constellations (Pavo - Sagittarius), that now get their names in the system of the General Catalogue of Variable Stars (GCVS). Also, GCVS names are assigned to 6 recent Novae and one young variable star in our Galaxy.
We present our study of 2MASS J23453766+7134365, an eclipsing variable star with a possible pulsating component, from a field in Cepheus. The star exhibits V-shaped eclipses with a depth of approximately 0.25 mag in the V band every 2.44 days; secondary minima are not detected. Also, sinusoidal brightness variations are detected with an amplitude of less than 0.1 mag and a period of 0.6791 days. They appear and disappear quasi-periodically with a characteristic time of several days. For the study of this star, we used the archive of Astrosib RC500 telescope (Mt. Terskol observatory). We conducted follow-up observations with the RC600 telescope (Caucasian Mountain Observatory) and Astrosib RC500 telescope (INASAN Kislovodsk observatory). Also, we used photometric data from the ZTF, ASAS-SN, and TESS surveys. |
