Accretion disc evolution in DW Ursae Majoris: A photometric study

Stanishev, V.; Kraicheva, Z.; Boffin, H. M. J.; Genkov, V.; Papadaki, C.; Carpano, S.

doi:10.1051/0004-6361:20034145

Cited by 25 publications

(31 citation statements)

References 34 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 hump at φ ≈ 0.75-0.9 corresponds to the bright spot at the impact site of the accretion stream with the disk edge. This feature is not always seen in light curves of DW UMa, but it is also not without precedent (e.g., a similar pre-eclipse hump is present in several of the many DW UMa light curves shown in Stanishev et al 2004).…”

Section: X-ray and Optical Light Curvesmentioning

confidence: 98%

“…Each light curve consists of approximately two orbital periods of phase coverage that were folded on the orbital period of Stanishev et al (2004). An offset of +1650 s was applied to the times of the OM data (which were recorded as seconds after 1998.0 UTC in the Terrestrial Time system) so that the center of the observed eclipse coincided exactly with the nearest-in-time zero point (φ = 0.0) of the Stanishev et al (2004) ephemeris. The same time offset was applied to the PN data.…”

Section: X-ray and Optical Light Curvesmentioning

confidence: 99%

“…More recent observations have extended into the mid-to farultraviolet (FUV, e.g., Knigge et al 2000Knigge et al , 2004Hoard et al 2003). DW UMa has an orbital period of 3.28 hr (Stanishev et al 2004) and a high inclination (i = 82 • ± 4 • ; AraujoBetancor et al 2003) that produces deep eclipses (e.g., see the optical and UV light curves in Shafter et al 1988 andKnigge et al 2004, respectively). By comparing UV spectra obtained during high and low states of DW UMa, Knigge et al (2000) and Knigge et al (2004) showed that the hot (T ≈ 50,000 K) WD in DW UMa is completely obscured by the optically thick accretion disk rim during the high state.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous X-Ray and Ultraviolet Observations of the Sw Sextantis Star Dw Ursae Majoris

Hoard

Knigge

et al. 2010

The Astronomical Journal

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We present the first pointed X-ray observation of DW Ursae Majoris, a novalike cataclysmic variable (CV) and one of the archetype members of the SW Sextantis class, obtained with the XMM-Newton satellite. These data provide the first detailed look at an SW Sex star in the X-ray regime (with previous X-ray knowledge of the SW Sex stars limited primarily to weak or non-detections in the ROSAT All Sky Survey). It is also one of only a few XMMNewton observations (to date) of any high mass transfer rate novalike CV, and the only one in the evolutionarily important 3-4 hr orbital period range. The observed X-ray spectrum of DW UMa is very soft, with ∼95% of the detected X-ray photons at energies <2 keV. The spectrum can be fit equally well by a one-component cooling flow model, with a temperature range of 0.2-3.5 keV, or a two-component, two-temperature thermal plasma model, containing hard (∼5-6 keV) and soft (∼0.8 keV) components. The X-ray light curve of DW UMa shows a likely partial eclipse, implying X-ray reprocessing in a vertically extended region, and an orbital modulation, implying a structural asymmetry in the X-ray reprocessing site (e.g., it cannot be a uniform corona). We also obtained a simultaneous near-ultraviolet light curve of DW UMa using the Optical Monitor on XMM-Newton. This light curve is similar in appearance to published optical-UV light curves of DW UMa and shows a prominent deep eclipse. Regardless of the exact nature of the X-ray reprocessing site in DW UMa, the lack of a prominent hard X-ray total eclipse and very low fraction of high energy X-rays point to the presence of an optically and geometrically thick accretion disk that obscures the boundary layer and modifies the X-ray spectrum emitted near the white dwarf.

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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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Accretion disc evolution in DW Ursae Majoris: A photometric study

Cited by 25 publications

References 34 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

Simultaneous X-Ray and Ultraviolet Observations of the Sw Sextantis Star Dw Ursae Majoris

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

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