相关论文: Late superhumps and the stream-disc impact in IY U…
CCD photometry of the newly discovered eclipsing dwarf nova IY UMa is used to study the physical properties of the accretion disc in the late decline and quiescence stages. Eclipse mapping analysis shows that in these stages the accretion…
Quiescent Doppler tomography of the newly discovered deeply-eclipsing SU UMa system IY UMa reveals properties of the region where the accretion stream from the donor impacts the edge of the disc. A very strong bright spot is produced and…
We present the analysis of hot spot brightness in light curves of the eclipsing dwarf nova IY Ursae Majoris during its normal outburst in March 2013 and in quiescence in April 2012 and in October 2015. Examination of four reconstructed…
We discovered a new deeply eclipsing SU UMa-type dwarf nova, IY UMa, which experienced a superoutburst in 2000 January. Our monitoring revealed two distinct outbursts, which suggest a superoutburst interval of ~800 d, or its half, and an…
We present high time-resolution photometry of the dwarf nova IY UMa using the S-Cam2 super-conducting tunnel junction device attached to the 4.2m William Herschel Telescope on La Palma. Exploiting the well-defined white dwarf and hot spot…
Superhump amplitudes observed in dwarf novae during their superoutbursts depend on orbital inclination: the maximum amplitudes in systems with low inclinations are $A_\circ \approx 0.25$ mag., while at higher inclinations they increase from…
Contribution from the irradiated secondary component is detected in the light curves of five dwarf novae observed during superoutbursts. Their superhump light curves show that irradiation is modulated with the superhump phase. This…
Oscillations observed in the light curve of Nova V1974 Cygni 1992 since summer 1994 have been interpreted as permanent superhumps. From simple calculations based on the Tidal-Disk Instability model of Osaki, and assuming that the accretion…
The evidence presented earlier by several authors for the substantial disk eccentricity in dwarf novae during their superoutbursts is shown to result either from errors or from arbitrary, incorrect assumptions. In particular, the evidence…
We exploit rare observations covering the time before and during a normal outburst in the deeply-eclipsing SU UMa system IY UMa to study the dramatic changes in the accretion flow and emission at the onset of outburst. Through Doppler…
Further evidence is presented supporting the alternative interpretation of superhumps as being due to irradiation modulated periodically variable mass transfer rate. NZ Boo, HT Cas and PU UMa are added to the sample of high inclination…
The eclipsing novalike cataclysmic variable star V348 Pup exhibits a persistent luminosity modulation with a period 6 per cent longer than its 2.44 hour orbital-period (Porb). This has been interpreted as a `positive superhump' resulting…
We present simultaneous $g'$, $R_{\rm c}$, and $I_{\rm c}$ photometry of the notable dwarf nova ER UMa during the 2011 season. Our photometry revealed that the brightness maxima of negative superhumps coincide with the bluest peaks in $g' -…
We consider accretion discs in close binary systems. We show that heating of a disc at the impact point of the accretion stream contributes significantly to the local energy budget at its outer edge. As a result the thermal balance relation…
We present photometric observations of the dwarf nova 1RXS J053234.9+624755. We performed a detailed analysis of the superoutburst that occurred in August 2009. We found the superhump period to be P_sh=0.057122(14)days. Based on the O-C…
We present the results of a search for the donor star in the high inclination SU UMa type cataclysmic variable IY UMa. We detect absorption features in the near infrared consistent with an M type dwarf donor star. Using the skew mapping…
Continuing the project described by Kato et al. (2009, PASJ, 61, S395, arXiv:0905.1757), we collected times of superhump maxima for 56 SU UMa-type dwarf novae mainly observed during the 2013-2014 season and characterized these objects. We…
We have discovered a dwarf nova (DN) of type SU UMa in Kepler data which is 7.0 arcsec from the G-type exoplanet survey target KIC 4378554. The DN appears as a background source in the pixel aperture of the foreground G star. We extracted…
We present multi-epoch, time-resolved optical spectroscopic observations of the dwarf nova HT Cas, obtained during 1986, 1992, 1995 and 2005 with the aim to study the properties of emission structures in the system. We determined that the…
We studied the evolution of superhumps in the peculiar SU UMa-type dwarf nova, ER UMa. Contrary to the canonical picture of the SU UMa-type superhump phenomena, the superhumps of ER UMa show an unexpected phase reversal during the very…