Related papers: The He-shell flash in action: T Ursae Minoris revi…
The AAVSO-based historical light curve of the oxygen-rich Mira variable R Leonis is used to determine and analyse the properties of the star's maxima and minima. The pulsation period is found to have shortened by about 3 days over the past…
Some Miras -- long-period variables in late evolutionary stages -- have meandering pulsation periods and light curve asymmetries, the causes of which are still unclear. We aim to understand better the origin of these phenomena by…
We present new multiband CCD photometry for AA UMa made on 8 nights between January and March 2009; the $R$ light curves are the first ever compiled. Historical light curves, as well as ours, display partial eclipses and inverse O'Connell…
We reobserved in the $R_C$ and $i'_{Sloan}$ bands, during the years 2020-2021, seven Mira variables in Cassiopeia, for which historical $i'_{Sloan}$ light curves were available from Asiago Observatory plates taken in the years 1967-84. The…
The subject of micro-variability among Mira stars has received increased attention since DeLaverny et al. (1998) reported short-term brightness variations in 15 percent of the 250 Mira or Long Period Variable stars surveyed using the…
Most aspects of stellar evolution proceed far too slowly to be directly observable in a single star on human timescales. The thermally pulsing asymptotic giant branch is one exception. The combination of state-of-the-art modelling…
We report photometry results of a frequently outbursting dwarf nova, ER Ursae Majoris. To measure the outburst parameters of the system, we carried out analyses of the light curve, periodograms, and O-C diagrams. We investigated the…
We examined data on about 20 years of observations of ER UMa available in AAVSO, VSNET, AFOEV, NSVS, VSOLJ databases together with published light curves. The obtained O-C diagram revealed a systematic change of the supercycle (time…
This study presented a new analysis for the TESS-observed W Ursae Majoris (W UMa) binary star YY Coronea Borealis (YY CrB). The light curve was analyzed by the PHysics Of Eclipsing BinariEs (PHOEBE) Python version together with the Markov…
Stellar evolution calculations were carried out from the main sequence to the final AGB stage of stars with initial masses from 1 to $2M_\odot$ and metallicity $Z=0.01$. Selected models of evolutionary sequences were used as initial…
Time-resolved CCD photometry is presented of the recently-discovered (V~15 at maximum light) eruptive variable star in Taurus, which we dub VS0329+1250. A total of ~20 hr of data obtained over six nights reveals superhumps in the light…
We report extensive photometry of the frequently outbursting dwarf nova RZ Leo Minoris. During two seasons of observations we detected 12 superoutbursts and 7 normal outbursts. The V magnitude of the star varied in range from 16.5 to 13.9…
We present a study of the orbital light curves of the recurrent nova IM Normae since its 2002 outburst. The broad "eclipses" recur with a 2.46 hour period, which increases on a timescale of 1.28(16)x10^6 years. Under the assumption of…
The variation of average brightness during the time and the variation of the amplitude of the Mira-type stars T Cep, X CrB, U UMi, U Cyg, BG Cyg is studied. For the research, the observations of the members of the French association of…
Pulsation period decrease during the initial stage of the thermal pulse in the helium-burning shell of the Mira-type variable T UMi is investigated with numerical methods of stellar evolution and radiation hydrodynamics. To this end, a grid…
ZZ UMa is a detached eclipsing binary with an orbital period of 2.299 d that shows total eclipses and starspot activity. We used five sectors of light curves from the Transiting Exoplanet Survey Satellite (TESS) and two published sets of…
We report the results of a long campaign of time-series photometry on the nova-like variable UX Ursae Majoris during 2015. It spanned 150 nights, with ~1800 hours of coverage on 121 separate nights. The star was in its normal `high state'…
Context: In a recent publication, we established a close relationship between light-curve asymmetries in Mira variables and indicators of their dust mass-loss rate. The light-curve asymmetries appear to be related to the stars' third…
We report an analysis of photometric behaviour of DI UMa, an extremely active dwarf nova. The observational campaign (completed in 2007) covers five superoutbursts and four normal outbursts. We examined principal parameters of the system to…
We performed a detailed analysis of extensive photometric observations of a sample of most active dwarf novae, that is SU UMa stars which are characterised by supercycle lengths shorter than 120 days. We found the observational evidence…