Publications
Section: PZ: main journal
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We present a new study of 123 known RR Lyrae variable stars from the Catalina surveys periodic variable star catalog. We analyzed all observations available for these stars in the Catalina Surveys online public archives using the period-search software developed by Dr. V.P. Goranskij for Windows environment. According to these data, the stars are double-mode RR Lyrae variables, pulsating in the first-overtone and fundamental modes.
GCVS names are announced for 13 galactic variable stars of rare types (mostly Novae) discovered in 2013-2015.
We present the results of our new observations of QS Draconis, a recently discovered double-mode high-amplitude Delta Scuti variable, HADS(B) type. We analyzed our CCD BVR photometry for this star, improved the frequencies f0 and f1 and pulsation amplitudes, detected the interaction frequencies f1+f0, f1-f0, 2f0, and f1+2f0.
We present a new study of 56 known RR Lyrae variable stars from the Catalina surveys periodic variable star catalog. We analyzed all observations available for these stars in the Catalina Surveys and SuperWASP online public archives using the period-search software developed by Dr. V.P. Goranskij for Windows environment. According to these data, the stars are double-mode RR Lyrae variables, pulsating in the first-overtone and fundamental modes.
We present the results of spectroscopy and CCD photometry of the intermediate-luminosity red transient PSN J13100734+3410514 in the galaxy UGC 8246 performed in February and June 2014 with the Russian 6-meter telescope and SCORPIO spectral camera. Our CCD photometry was continued with the Special Astrophysical Observatory's 1-m telescope till November 2014. The star was discovered in late December 2013 at visual brightness 17.6m, which corresponded to the absolute magnitude MV = -12.7m, and was identified as a supernova impostor. Spectra taken at the visual brightness level of 19.5m show composite triple profiles in the Halpha and Hbeta emission lines. We explain the main component of the profiles as radiation from a photoionized extensive gaseous envelope formed by the stellar wind of the progenitor before the outburst. The other two components are treated as radiation from bipolar ejecta. In Balmer line profiles, there is an evidence for a light echo propagating in the surrounding medium after the outburst. Our spectra contain emissions of He I, Na I, Mg I, numerous Fe II emissions, the strongest of which have P Cyg profiles. There are also [O II], [O III], and [S II] emissions of an H II region associated with the transient. The emissions of the region are superimposed on the star spectrum. The light curves show rapid decline and color reddening. Our observations confirm that the UGC 8246 transient was an explosion of a high-mass LBV star.
We present a new study of 28 known RR Lyrae variable stars. We analyzed all observations available for these stars in the Catalina Surveys, LINEAR, Northern Sky Variability Survey, and SuperWASP online public archives using the period-search software developed by Dr. V.P. Goranskij for Windows environment. According to these data, the stars are double-mode RR Lyrae variables, pulsating in the first-overtone and fundamental modes.
CCD BVRI photometry is presented for type II Supernovae 2009af and 2009ay. Both objects are characterized by fast linear brightness decline at early stages of their evolution and relatively high maximum luminosity. SN 2009af is distinguished by a small brightness drop during the first 200 days after maximum.
We present our discovery of a new double-mode high-amplitude delta Scuti variable, HADS(B) type, USNO-B1.0 1329-0132547. We found the frequencies f0=6.1770 and f1=8.0561. The period ratio P1/P0 = 0.7668 is typical of radially pulsating HADS(B) stars.
From our comparison of magnitudes of bright stars in the Hipparcos catalogue and in the Tien-Shan catalogue of WBVR magnitudes, we compiled a list of stars that could be candidate photometric standards in the northern sky. The selected stars were tested for variability using the MZ technique. The result is a list of 6484 stars recommended as standards.
The new variable star HD 305629, with a Cepheid-like light curve, is demonstrated, from our optical observations and ASAS-3 data, to actually be an ellipsoidal variable star on a highly eccentric orbit. It resembles the X-ray variable star BP Cru. HD 305629 deserves further observations in other wavelengths. |
