Quasi-periodic Oscillations in the Cataclysmic Variable KR Aurigae

Singh, Jyoti; Rao, P. Vivekananda; Agrawal, P. C.; Apparao, K. M. V.; Manchanda, R. K.; Sanwal, B. B.; Sarma, M. B. K.

doi:10.1086/173487

Cited by 8 publications

(5 citation statements)

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“…We have not been able to confirm the presence of 25-min periodicity claimed by Biryukov, Borisov (1990). The periods of the presently observed QPOs are close to the periodicities (480-780 s) recorded by Singh et al (1993). We have also confirmed night-to-night variation of dominant periods as was originally claimed by Singh et al (1993).…”

Section: Short-term Variationssupporting

confidence: 89%

Photometric Study of KR Aurigae during the High State in 2001

Katô

Ishioka

Uemura

2002

Publications of the Astronomical Society of Japan

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We photometrically observed the VY Scl-type cataclysmic variable KR Aurigae after its final rise from the fading episode in 2000-2001. Time-resolved observation revealed that the light curve is dominated by persistent short-term variation with time-scales of minutes to tens of minutes. On some nights, quasiperiodic variations with periods of 10-15 min were observed. No coherent variation was detected. The power spectral density of the variation has a power law component (f −1.63 ). The temporal properties of the short-term variations in KR Aur present additional support for the possibility that flickering in CVs may be better understood as a result of self-organized critical state as in black-hole candidates. The light curve lacks "superhump"-type signals, which are relatively frequently seen in VY Scl-type systems and which are suggested to arise from tidal instability of the accretion disk induced by changing mass-transfer rates. The present observation suggests a borderline of superhump excitation in VY Scl-type stars between mass ratios q=0.43 (MV Lyr) and q=0.60 (KR Aur).

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Section: Short-term Variationssupporting

confidence: 89%

Photometric Study of KR Aurigae during the High State in 2001

Katô

Ishioka

Uemura

2002

Publications of the Astronomical Society of Japan

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“…The brightness of KR Aur is usually between 12 and 14 mag, with occasional decreases to 15.5 mag, but it drops to 18 mag occasionally. Singh et al (1993) detected large‐amplitude quasi‐periodic oscillations (QPOs) in this star, with periods in the range 500–800 s. There were also indications of a modulation with a period of about 4 h. This modulation might represent the orbital period or might be a type of superhump. However, Kato, Ishoka & Uemura (2002) conducted photometric observations of KR Aur and found no modulation with such a period.…”

Section: Introductionmentioning

confidence: 78%

Detection of superhumps in the VY Scl-type nova-like variable KR Aur

Kozhevnikov¹

2007

Monthly Notices of the Royal Astronomical Society

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We report on detection of negative superhumps in KR Aur which is the representative member of the VY Scl stars. The observations were obtained with the multi-channel photometer during 107 h. The analysis of the data clearly revealed brightness variations with a period of 3.771 +/- 0.005 h. This is 3.5 per cent less than the orbital period, suggesting it is a negative superhump. Negative superhumps in VY Scl stars are widely spread. The discovery of powerful soft X-rays from V751 Cyg demonstrates that VY Scl stars may contain white dwarfs, at which nuclear burning of the accreted material occur. If this suspicion is correct, we then can suppose that the powerful radiation emerging from the white dwarf may cause the tilt of the accretion disk to the orbital plane, and its retrograde precession may produce negative superhumps in VY Scl stars.Comment: 6 pages, 6 figures, will be published in MNRA

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“…The periods of QPOs are about 5-10-15 min, but sometimes were detected longer periods -about 20 min or even 40 min (Georgiev et al, 2012). These periods change from night to night (Singh et al, 1993). Probably on short scales (5-10 min) the variations are stochastic, but on larger scales they have another…”

Section: Flickering In High Statementioning

confidence: 99%