E. A. Karitskaya

Photometric and spectroscopic study of nova Cassiopeiae 1995 (V723 Cas)

We report an 11-year long series of U BV RI observations and the results of our monitoring of the classical slow nova V723 Cas. We analyze the spectra of this star taken using the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences with a spectral resolution of 3.5–8.5 Å during the nebular stage and at the supersoft X-ray source phase (SSS). This systemhas a large orbital inclination and its orbital period is equal to 0.693265 days. The orbital period increases. We found low-amplitude light variations with the orbital period during the early stages of the outburst and even at the pre-maximum stage. The orbital light curve at the nebular stage is asymmetric and gradually increases its amplitude up to V=2m in 2006. The asymmetry of the light curve of V723 Cas can be explained by the reflection effect, eclipse of the extended accretion disk, and high rate of mass transfer in the system. The light curve of V723 Cas has developed a plateau due to the SSS phase. In the spectrum of V723 Cas the transition to the SSS phase shows up in an order-of-magnitude increase of the flux of the [Fe X] λ 6374 Å emission, which forms in the expanding envelope. In addition, narrow emission lines λ 6466.4 Å (O V) and λ 6500.5 Å (Fe XVII) also emerged in the spectrum.

THE INVESTIGATION OF CONTEMPORARY CLASSICAL NOVAE

Abstract The investigation of five classical novae: N Cyg 1992 = V1974 Cyg, N Aql 1993 = V1419 Aql, N Cas 1993 = V705 Cas, N Aql 1995 and N Cas 1995 is reported in this paper. The identifications of these novae with faint stars in the Palomar Sky Survey were checked. N Aql 1993 was identified with a star of 21 mag on the POSS O plate. The light curves and the colour index variation curves were obtained using original observations by the authors and other published data. The behaviour of several type classical novae and X-ray novae in the two-colour diagrams is found to be considerably different. The appearance of two light periodicities in N Cas 1992 in the late stages of outburst is confirmed, but the observations can not be fitted by any linear elements in a time interval of more than 200 d.

Optical pre-nova identification for the X-ray Nova GRO JO422 +32 (nova persei, 1992)

Abstract The X-ray Nova GRO JO422+32 in its low brightness has been identified with a faint star on both blue and red Palomar Sky Survey glass copies (see Figures 1 and 2). The scans obtained with an automatic microdensitometer were processed with our special PC program to strengthen the contrast of the image. The magnitudes measured are the following: B, 20m.9 ± Om.3; R = 20m.1 ± Om.5. The resulting outburst amplitude 7m.7 ± Om.6 is one of similarity features for the class of the low mass X-ray Novae black hole candidates.

Optical pre-nova identification for the X-ray Nova GRO J0422+32 (Nova Persei, 1992)

The X-ray Nova GRO J0422+32 in its low brightness has been identified with a B∼ 21m, R∼20m star on Palomar Sky Survey glass copies. The scans obtained with an automatical microdensitometer along with our special PC program were used. The resulting outburst amplitude 8m is one of similarity features for the class of the low mass X-ray Novae, black hole candidates.