Search Publications
Recurrent Symbiotic Nova T Coronae Borealis before Outburst
Strakhov, I. A.; Tatarnikov, A. M.; Shenavrin, V. I. +5 more
The results of photometric and spectral observations of T CrB obtained in a wide range of wavelengths in 2011-2023 are presented. We use the near-IR light curves to determine a new ephemeris $JD_{\textrm{min}}=2455828.9+227.55E$ for the times of light minima when the red giant is located between the observer and the hot component. The flux ratio H…
Surprising Variability of the Planetary Nebula IC 4997 = QV Sge
Arkhipova, V. P.; Esipov, V. F.; Ikonnikova, N. P. +3 more
We present the results of a new epoch (2009-2019) of a long-term (50 years) photometric monitoring of the variable planetary nebula IC 4997 (QV Sge). The integral (star + nebula) $UBV$ light curves display a continuing brightening of $0\overset{m}{.}15$ in $V$, a slight rise (${<}0\overset{m}{.}1$) in $B$, and constancy in $U$. The $B-V$ color …
Peculiarities of the accretion flow in the system HL CMa
Lutovinov, A. A.; Revnivtsev, M. G.; Semena, A. N. +2 more
The properties of the aperiodic luminosity variability for the dwarf novaHLCMa are considered. The variability of the system HL CMa is shown to be suppressed at frequencies above 0.7 × 10-2 Hz. Different variability suppression mechanisms related to the radiation reprocessing time, partial disk evaporation, and characteristic variabilit…
Relation between the X-ray and optical luminosities in binary systems with accreting nonmagnetic white dwarfs
Revnivtsev, M. G.; Suleimanov, V. F.; Filippova, E. V.
We investigate the relation between the optical ( g-band) and X-ray (0.5-10 keV) luminosities of accreting nonmagnetic white dwarfs. According to the present-day counts of the populations of star systems in our Galaxy, these systems have the highest space density among the close binary systems with white dwarfs. We show that the dependence of the …
Ultraviolet spectrum of FU Ori and a ``Compromise'' model of the FUor
Errico, L.; Lamzin, S. A.; Kravtsova, A. S. +1 more
We have analyzed the Hubble Space Telescope spectrum of the young star FU Ori in the range 2300 3100 Å. The long-wavelength part of the spectrum is similar to the spectrum of a supergiant with T eff ≃ 5000 6000 K, but the range of wavelengths shorter than ≃2600 Å is dominated by radiation from a region with T eff ≃ 9000 K. We…
Variability of the H_alpha and Na I D Line Profiles in the Spectrum of FU Ori
Errico, L.; Lamzin, S. A.; Vittone, A.
The variations of line profiles in the spectrum of FU Ori during several consecutive nights, from January 3 through January 8, 1999, have been traced for the first time in the entire history of studying this star. The variations of the H_alpha and Na I D line profiles are regular in pattern; at each time, the profiles of these lines were similar t…
Peculiarities of the UV Continuum Energy Distribution for T Tauri Stars
Lamzin, S. A.; Kravtsova, A. S.
In the UV spectra of BP Tau, GW Ori, T Tau, and RY Tau obtained with the Hubble Space Telescope, we detected an inflection near 2000 Angstrems in the F^clambda(lambda) curve that describes the continuum energy distribution. The inflection probably stems from the fact that the UV continuum in these stars consists of two components: the e…
A study of the radial velocity of the star theta 1 Ori C.
Vitrichenko, E. A.
A Preliminary Radial-Velocity Curve for the Star θ1 Ori D
Vitrichenko, É. A.
A minimum in the light curve of the classical symbiotic star YY Her in 2001.
Kolotilov, E. A.; Yudin, B. F.; Tatarnikova, A. A. +1 more