High-speed photometry of the dwarf nova Z Cha in quiescence

Wood, Janet H.; Horne, K.; Berriman, G. Bruce; Wade, Richard A.; O’Donoghue, D.; Warner, Brian D.

doi:10.1093/mnras/219.3.629

Cited by 169 publications

(166 citation statements)

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“…Disc radius variations are indeed observed in dwarf novae, and the disc in IP Pegasi fills between half of the primary Roche lobe during quiescence up to most of the Roche lobe during outburst [34,32,25]. Tidally driven waves are thus much more likely to have an effect on the disc in outburst, since the tidal torques are a steep function of the distance to the secondary star.…”

Section: The Quiescent Discmentioning

confidence: 99%

Spiral Waves in Accretion Discs— Observations

Steeghs

2001

Astrotomography

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Abstract. I review the observational evidence for spiral structure in the accretion discs of cataclysmic variables (CVs). Doppler tomography is ideally suited to resolve and map such co-rotating patterns and allows a straightforward comparison with theory. The dwarf nova IP Pegasi presents the best studied case, carrying two spiral arms in a wide range of emission lines throughout its outbursts. Both arms appear at the locations where tidally driven spiral waves are expected, with the arm closest to the gas stream weaker in the lines compared to the arm closest to the companion. Eclipse data indicates sub-Keplerian velocities in the outer disc. The dramatic disc structure changes in dwarf novae on timescales of days to weeks, provide unique opportunities for our understanding of angular momentum transport and the role of density waves on the structure of accretion discs. I present an extension to the Doppler tomography technique that relaxes one of the basic assumptions of tomography, and is able to map modulated emission sources. This extension allows us to fit anisotropic emission from, for example, spiral shocks, the irradiated companion star and disc-stream interaction sites.

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Section: The Quiescent Discmentioning

confidence: 99%

Spiral Waves in Accretion Discs— Observations

Steeghs

2001

Astrotomography

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“…Classical examples of dwarf 2 This number is smaller than the total number of eclipses listed in Table 2 because in a few cases the light curve does not cover the start of eclipse ingress. novae which exhibit this kind of eclipse profile are Z Cha (Wood et al 1986), OY Car (Wood et al 1989) and IP Peg (Bobinger et al 1999).…”

Section: Eclipse Profilementioning

confidence: 99%

Long-term photometry of the eclipsing dwarf nova V893 Scorpii

Bruch

2014

A&A

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Context. The cataclysmic variable V893 Sco is an eclipsing dwarf nova which, apart from outbursts with comparatively low amplitudes, exhibits a particularly strong variability during quiescence on timescales of days to seconds. Aims. The present study aims to update the outdated orbital ephemerides published previously, to investigate deviations from linear ephemerides, and to characterize non-random brightness variations in a range of timescales. Methods. Light curves of V893 Sco were observed on 40 nights, spanning a total time base of about 14 years. They contain 114 eclipses which were used to significantly improve the precision of the orbital period and to study long-term variations of the time of revolution. Oscillations and similar brightness variations were studied with Fourier techniques in the individual light curves. Results. The orbital period exhibits long-term variations with a cycle time of 10.2 years. They can be interpreted as a light travel time effect caused by the presence of a giant planet with approximately 9.5 Jupiter masses in a 4.5 AU orbit around V893 Sco. On some nights transient semi-periodic variations on timescales of several minutes can be seen which may be identified as quasi-periodic oscillations. However, it is difficult to distinguish whether they are caused by real physical mechanisms or if they are the effect of an accidental superposition of unrelated flickering flares. Simulations to investigate this question are presented.

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“…The most recent photometric study of the eclipses of Z Cha is by Wood et al (1986). This work makes use of a very well-defined average light curve obtained during a quiescent period in which the system properties (disc radius, etc.)…”

Section: Introductionmentioning

confidence: 99%

A Modern View of the Dwarf Nova Z Chamaeleontis

Wade

1987

International Astronomical Union Colloquium

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ABSTRACT, Some recent photometric and spectroscopic results for this "ultrashort" period system are summarized, and several straightforward consequences of these results for our understanding of the evolution of cataclysmic binaries are pointed out: The space motion of Z Cha is characteristic of the old disk population. The white dwarf cannot be composed primarily of He, unless it grew by accretion by at least 20%. The inferred masses of the component stars, combined with the usual gravitational quadrupole formula, probably do not suffice to explain the inferred rate of mass transfer, even in quiescence. The secondary star does not lie on the computed evolutionary tracks in the periodmass diagram of Paczynski and Sienkiewicz.

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High-speed photometry of the dwarf nova Z Cha in quiescence

Cited by 169 publications

References 0 publications

Spiral Waves in Accretion Discs— Observations

Spiral Waves in Accretion Discs— Observations

Long-term photometry of the eclipsing dwarf nova V893 Scorpii

A Modern View of the Dwarf Nova Z Chamaeleontis

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