Photometric study of selected cataclysmic variables

Papadaki, C.; Boffin, H. M. J.; Sterken, C.; Stanishev, V.; Cuypers, J.; Boumis, P.; Akras, S.; Alikakos, J.

doi:10.1051/0004-6361:20054679

Cited by 27 publications

(38 citation statements)

References 69 publications

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“…Only nine SW Sex stars in the list of Rodríguez-Gil et al (2007) have eclipse depths above 2.0 mag, which are, however, lower than that of J0107. Two SW Sex stars, DW UMa (Stanishev et al 2004) and V1315 Aql (Papadaki et al 2009), have shown deeper eclipses of 3.2-3.4 mag, but only once and only within 2-3 days, whereas normally their eclipse depths are below 2.0 mag. Therefore, 2MASS J01074282+4845188 has the deepest permanent eclipse (at least during 11 months) among the known eclipsing nova-like variables.…”

Section: Photometrymentioning

confidence: 99%

The SW Sextantis-type star 2MASS J01074282+4845188: an unusual bright accretion disk with non-steady emission and a hot white dwarf

Khruzina

Dimitrov

Kjurkchieva

2013

A&A

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Context. Cataclysmic variables (CVs) present a short evolutional stage of binary systems. The nova-like stars are rare objects, especially those with eclipses (only several tens). But precisely these allow to determine the global parameters of their configurations and to learn more about the late stage of stellar evolution. Aims. The light curve solution allows one to determine the global parameters of the newly discovered nova-like eclipsing star 2MASS J01074282+4845188 and to estimate the contribution of the different light sources. Methods. We present new photometric and spectral observations of 2MASS J01074282+4845188. To obtain a light curve solution we used a model of a nova-like star whose emission sources are a white dwarf surrounded by an accretion disk, a secondary star filling its Roche lobe, a hot spot and a hot line. The obtained global parameters are compared with those of the eclipsing nova-like UX UMa. Results. 2MASS J01074282+4845188 shows the deepest permanent eclipse among the known nova-like stars. It is reproduced by covering the very bright accretion disk by the secondary component. The luminosity of the disk is much bigger than that of the rest light sources. The determined high temperature of the disk is typical for that observed during the outbursts of CVs. The primary of 2MASS J01074282+4845188 is one of the hottest white dwarfs in CVs. The temperature of 5090 K of its secondary is also quite high and more appropriate for a long-period SW Sex star. It might be explained by the intense heating from the hot white dwarf and the hot accretion disk of the target. Conclusions. The high mass accretion rateṀ = 8 × 10 −9 M yr −1 , the broad and single-peaked Hα emission profile, and the presence of an S-wave are sure signs for the SW Sex classification of 2MASS J01074282+4845188. The obtained flat temperature distribution along the disk radius as well as the deviation of the energy distribution from the black-body law are evidence of the non-steady emission of the disk. It can be attributed to the low viscosity of the disk matter due to its unusual high temperature. The close values of the disk temperature and the parameter α g of 2MASS J01074282+4845188 and those of the cataclysmic stars at eruptions might be considered as an additional argument for the permanent active state of nova-like stars.

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Section: Photometrymentioning

confidence: 99%

The SW Sextantis-type star 2MASS J01074282+4845188: an unusual bright accretion disk with non-steady emission and a hot white dwarf

Khruzina

Dimitrov

Kjurkchieva

2013

A&A

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“…The light curves on which the present newly derived value is based are quite noisy, and so is the folded light curve. Moreover, old novae and novalike variables frequently exhibit (positive or negative) superhumps which are unstable over long time scales but in a limited data set may mimick orbital variations Examples include V603 Aql (Haefner & Metz 1985, Bruch 1991, Patterson et al 1993), TT Ari (Belova et al 2013 and references therein; Smak 2013), KR Aur (Kozhevnikov 2007), V751 Cyg (Patterson et al 2001, Papadaki et al 2009), V795 Her (Papadaki et al 2006), and V378 Peg (Kozhevnikov 2012). This issue as well as that of a possible giant nature of the secondary star (Sect.…”

Section: The Photometric Periodmentioning

confidence: 99%

Photometry of some more neglected bright cataclysmic variables and candidates

Bruch

2018

New Astronomy

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As part of an effort to better characterize bright cataclysmic variables (CVs) and related systems which have received little attention in the past light curves of four systems (V504 Cen, KT Eri, Ret 1 and CTCV 2056-3014) are analyzed. For some of these stars no time resolved photometry has been published previously. While flickering is observed in all systems except Ret 1, it is particularly strong in V504 Cen and CTCV 2056-3014. In the latter star, a previously observed 15.4 m period, leading to its tentative classification as an intermediate polar, is probably spurious. Variations on time scales of hundredths of days observed in the pre-outburst light curve of the classical nova KT Eri continue after the outburst but appear not to be strictly periodic. Furthermore, the long term post-outburst light curve exhibits modulations with quasi-periods of quite different length. Thus, these variations cannot be due to aspect related variations in a system with a giant component similar to some recurrent novae. Instead, the system possibly exhibits variations with a period of 0.1952 d which may be orbital. However, any such conclusion still requires confirmation. The absence of flickering in Ret 1 indicates that the system probably does not contain an accretion disk. Instead, the observation of slow variations supports a previous suspicion of low amplitude variability with a period >12 h.

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“…Only nine SW Sex stars in the list of Rodriguez-Gil et al (2007) have eclipse depths more than 2.0 mag (Khruzina et al 2013). Two SW Sex stars, DW UMa (Stanishev et al 2004) and V1315 Aql (Papadaki et al 2009), normally have eclipse depths less than 2.0 mag, but on rare occasions and only within two to three days do they show deeper eclipses of 3.2−3.4 mag. Dimitrov & Kjurkchieva (2012) report the SW Sex star 2MASS J01074282+4845188 with an eclipse depth of V ∼ 2.9 mag, but the newly discovered cataclysmic star J2256 turned out to have an even deeper eclipse.…”

Section: Initial Analysismentioning

confidence: 98%

2MASS J22560844+5954299: the newly discovered cataclysmic star with the deepest eclipse

Kjurkchieva

Khruzina

Dimitrov

et al. 2015

A&A

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Context. The SW Sex stars are assumed to represent a distinguished stage in cataclysmic variable (CV) evolution, making it especially important to study them. Aims. We discovered a new cataclysmic star and carried out prolonged and precise photometric observations, as well as mediumresolution spectral observations. Modelling these data allowed us to determine the physical parameters and to establish its peculiarities. Methods. To obtain a light curve solution we used model whose emission sources are a white dwarf surrounded by an accretion disk with a hot spot, a gaseous stream near the disk's lateral side, and a secondary star filling its Roche lobe. The obtained physical parameters are compared with those of other SW Sex-subtype stars. Results. The newly discovered cataclysmic variable 2MASS J22560844+5954299 shows the deepest eclipse amongst the known nova-like stars. It was reproduced by totally covering a very luminous accretion disk by a red secondary component. The temperature distribution of the disk is flatter than that of steady-state disk. The target is unusual with the combination of a low mass ratio q ∼ 1.0 (considerably below the limit q = 1.2 of stable mass transfer of CVs) and an M-star secondary. The intensity of the observed three emission lines, Hα, He 5875, and He 6678, sharply increases around phase 0.0, accompanied by a Doppler jump to the shorter wavelength. The absence of eclipses of the emission lines and their single-peaked profiles means that they originate mainly in a vertically extended hot-spot halo. The emission Hα line reveals S-wave wavelength shifts with semi-amplitude of around 210 km s −1 and phase lag of 0.03. Conclusions. The non-steady-state emission of the luminous accretion disk of 2MASS J22560844+5954299 was attributed to the low viscosity of the disk matter caused by its unusually high temperature. The star shows all spectral properties of an SW Sex variable apart from the 0.5 central absorption.

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Photometric study of selected cataclysmic variables

Cited by 27 publications

References 69 publications

The SW Sextantis-type star 2MASS J01074282+4845188: an unusual bright accretion disk with non-steady emission and a hot white dwarf

The SW Sextantis-type star 2MASS J01074282+4845188: an unusual bright accretion disk with non-steady emission and a hot white dwarf

Photometry of some more neglected bright cataclysmic variables and candidates

2MASS J22560844+5954299: the newly discovered cataclysmic star with the deepest eclipse

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