Spectroscopy of TT Arietis in "positive superhumps"
state

Stanishev, V.; Kraicheva, Z.; Genkov, V.

doi:10.1051/0004-6361:20011312

Cited by 13 publications

(16 citation statements)

References 35 publications

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“…Hollander & van Paradijs (1992) proposed a dependence of QPO characteristics on accretion rate. Kraicheva et al (1999) and Stanishev et al (2001) suggested variations in the accretion rate as a cause of switches between the positive and negative superhumps, and reported that in the positive superhump state the Article published by EDP Sciences flickering amplitude is smaller than in the brighter superhump state.…”

Section: Introductionmentioning

confidence: 99%

Nova-like cataclysmic variable TT Arietis

Kim

Андронов

et al. 2009

A&A

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Aims. We study the variability of the nova-like cataclysmic variable TT Ari, on time-scales of between minutes and months. Methods. The observations in the filter R were obtained at the 40-cm telescope of the Chungbuk National University (Korea), 51 observational runs cover 226 h. The table of individual observations is available electronically. In our analysis, we applied several methods: periodogram, wavelet, and scalegram analysis. Results. TT Ari remained in a "negative superhump" state after its return from the "positive superhump" state, which lasted for 8 years.The ephemeris for 12 of the best pronounced minima is T min = BJD 2 453 747.0700(47) + 0.132322(53)E. The phases of minima may reach 0.2, which reflects the non-eclipse nature of these minima. The quasi-periodic oscillations (QPO) are present with a mean "period" of 21.6 min and mean semi-amplitude of 36 mmag. This value is consistent with the range 15−25 min reported for previous "negative superhump" states and does not support the hypothesis of secular decrease in the QPO period. Either the period, or the semi-amplitude show significant night-to-night variations. According to the position at the two-parameter diagrams (i.e. diagrams of pairs of parameters: time, mean brightness of the system, brightness of the source of QPO, amplitude, and timescale of the QPOs), the interval of observations was divided into 5 parts, showing different characteristics: 1) the "pre-outburst" stage; 2) the "rise to outburst"; 3) "top of the outbursts"; 4) "post-outburst QPO" state; and 5) "slow brightening". The the QPO source was significantly brighter during the 10-day outburst, than during the preceding interval. However, after the outburst, the large brightness of the QPO source still existed for about 30 days, producing the stage "4". The diagram for m QPO (m) exhibits two groups in the brightness range 10. m 6−10. m 8, which correspond to larger and smaller amplitudes of the QPO. For the group "5" only, statistically significant correlations were found, for which, with increasing mean brightness, the period, amplitude, and brightness of the of QPO source also increase. The mean brightness at the "negative superhump state" varies within 10. m 3−11. m 2, so the system is brighter than at the "positive superhump" (11. m 3), therefore the "negative superhump" phenomenon may be interpreted by a larger accretion rate. The system is an excellent laboratory for studying processes resulting in variations on timescales of between seconds and decades and needs further monitoring at various states of activity.

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Section: Introductionmentioning

confidence: 99%

Nova-like cataclysmic variable TT Arietis

Kim

Андронов

et al. 2009

A&A

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“…Our first observations of TT Ari [13] yielded some interesting details that differed from earlier data [8,12]. In particular, the Hγ emission line and the anti P Cygni Hα line profile were found to be absent.…”

Section: Introductionmentioning

confidence: 51%

“…It is assumed that broad absorption develops in the inner layers of the accretion disk and in the photosphere of the white dwarf, and subsequently broadens further owing to the pressure effect [12,13] and, to some extent, owing to the star's rapid rotation.…”

Section: Introductionmentioning

confidence: 99%

Spectral and photometric observations of TT Ari. III.

et al. 2010

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The nova-like cataclysmic variable (CV) TT Ari was detected in its second deep minimum inNovember 2009. Study of its evolutionary phase is very important for research on the nature of CVs in the VY Scl group. During this phase the spectral energy distribution of the star changed rapidly. The emission lines of elements with high excitation, such as HeII λ4686 and NIII/CIII, as well as broad absorption in the hydrogen Balmer series, originating in the photosphere of the white dwarf or in the lower layers of an accretion disk, vanished. The average ratio of the intensities of the Balmer series emission lines in the normal state and in the deep low state can be explained in terms of a simple photoionization-recombination model. At the same time, the intensity ratios of the triplet-singlet levels of neutral helium, HeIλ5876/ HeIλ6678, differ greatly in the normal state of the star and in its deep minimum. In the deep minimum, the star's spectrum contains only a very faint trace of the G band at a wavelength λ4300Å, together with flarelike events with amplitudes up to 0 2 m . m ≈ Δ or greater. These and some other observed characteristicsindicate that during the deep minimum it is mainly emission from the secondary companion of the binary system, which is probably a T Tau star of an early K spectral class, that is observed.

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“…(1) Patterson & Warner (1998), (2) Mason et al (2013), ( Skillman et al (1995), (25) Stanishev et al (2004), (26) Stanishev et al (2001), (27) Patterson (2001), (28) Kato & Uemura (2001), (29) Patterson et al (2005), (30) Retter et al (2003) Remarks: (a) shows also negative superhumps (b) possibly asynchronous rotation of the white dwarf (see more detail in the text) (c) possibly the remnant of a classical nova, observed on 101 December 30 (Patterson et al 2013) odicity could correspond to the spin of the magnetic white dwarf of this system that rotates nearly synchronously with the orbital revolution. However, it would be a very strange coincidence that the white dwarf rotation fits quite well the Stolz-Schoembs relation; we therefore believe that we could have a superhump also in this case.…”

Section: Rr Pic In Context With Other Superhumpersmentioning

confidence: 99%

Photometric long-term variations and superhump occurrence in the Classical Nova RR Pictoris

Fuentes-Morales¹,

Vogt²,

Tappert³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present an analysis of all available time-resolved photometry from the literature and new light curves obtained in 2013-2014 for the old nova RR Pictoris. The well-known hump light curve phased with the orbital period reveals significant variations over the last 42 years in shape, amplitude and other details which apparently are caused by long-term variations in the disc structure. In addition we found evidence for the presence of superhumps in 2007, with the same period (∼9% longer than the orbital period), as reported earlier by other authors from observations in 2005. Possibly, superhumps arise quickly in RR Pic, but are sporadic events, because in all the other observing runs analysed no significant superhump signal was detected. We also determined an actual version of the Stolz-Schoembs relation between superhump period and orbital period, analysing separately dwarf novae, classical novae and nova-like stars, and conclude that this relation is of general validity for all superhumpers among the cataclysmic variables (CVs), in spite of small but significant differences among the sub-types mentioned above. We emphasize the importance of such a study in context with the still open question of the interrelation between the different sub-classes of CVs, crucial for our understanding of the long-term CV evolution.

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Spectroscopy of TT Arietis in "positive superhumps" state

Cited by 13 publications

References 35 publications

Nova-like cataclysmic variable TT Arietis

Nova-like cataclysmic variable TT Arietis

Spectral and photometric observations of TT Ari. III.

Photometric long-term variations and superhump occurrence in the Classical Nova RR Pictoris

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