3 citations · 5 across the 12 of their papers we have counts for
12 papers
H_alpha observations of the Be/X-ray binary MWC 656
R. Zamanov, V. Marchev, K. A. Stoyanov +8
Context. MWC 656 is a Be/X-ray binary identified as an emission-line object, X-ray and radio source and might be a weak gamma-ray source, harbouring an enigmatic secondary componen…
BV photometry of the cataclysmic variable LY UMa
L. Dankova, D. Marchev, S. Peneva +1
We performed B- and V-band photometry of the probable dwarf nova LY UMa. We find that it has apparent magnitude V=15.26+/-0.03 on 2024-04-14, V=15.43+/-0.02 on 2025-04-28, and V =…
Is Mira B a low mass white dwarf?
R. K. Zamanov, V. Irincheva, B. Spassov +8
We report photometric observations in Johnson B and V bands of the short term variability (flickering) of Mira (omicron Ceti). The observations were performed during 7 nights in th…
Red giant component of the recurrent nova T Coronae Borealis
R. K. Zamanov, D. Marchev, V. Marchev +5
We performed simultaneous V band photometry and spectroscopic observations of the recurrent nova T CrB and estimate the V band magnitude of the red giant. We find for the red giant…
Interstellar extinction toward MWC 148
R. Zamanov, I. Stateva, J. Marti +2
We analyse high resolution optical spectra of MWC148 (optical counterpart of the gamma-ray source HESS J0632+057) obtained at Observatoire de Haute Provence and Rozhen Observatory.…
Evolution of the optical emission lines and the X-ray emission during the super-active stage of T CrB
K. A. Stoyanov, G. J. M. Luna, R. K. Zamanov +6
T CrB is a symbiotic star that experiences nova outbursts every 80~yr. The next, long-anticipated nova outburst should occur during the 2024-2026 period. Here, we present re…
Size of the accretion disc in the recurrent nova T CrB
R. K. Zamanov, K. A. Stoyanov, V. Marchev +7
We present high resolution (0.06 A/px) spectroscopic observations of the recurrent nova T Coronae Borealis obtained during the last 1.5 years (September 2022 -- January 2024), with…
Luminosity class of the symbiotic stars 4U1954+319 and ZZ CMi
R. Zamanov, K. A. Stoyanov, G. Latev +8
We performed optical photometry and spectral observations of the symbiotic stars 4U1954+319 and ZZ CMi. For 4U1954+319 using high-resolution spectra we measure the equivalent width…
A long-term study of the magnetic field and activity in the M giant RZ Ari
R. Konstantinova-Antova, S. Georgiev, A. Lèbre +12
We present a detailed long-term study of the single M6 III giant RZ~Ari to obtain direct and simultaneous measurements of the magnetic field, activity indicators, and radial veloci…
Macro-flickering of AQ Mensae on the daily time-scales: Parameters and quasi-period modes
Ts. B. Georgiev, R. K. Zamanov, S. Y. Stefanov
We analyzed TESS photometric data of the flickering-active cataclysmic star AQ Men in 2018--2019. We processed 7 sectors with 14 light curves (LCs) inside them, with a time resolut…
Accretion in the recurrent nova T CrB: Linking the superactive state to the predicted outburst
R. Zamanov, S. Boeva, G. Y. Latev +6
Context: T CrB (NOVA CrB 1946) is a famous recurrent nova with a recurrence timescale of 80 years. Aims: We aim to estimate the colours, luminosity, and mass-accretion rate for T C…
Mass accretion rate in the jet-driving symbiotic binary MWC 560
V. Marchev, R. Zamanov
We analyze photometric observations of the symbiotic star MWC 560 in B and V bands obtained during the period 1990-2023. We estimate the luminosity and the mass accretion rate of t…