Photometric and Hα Observations of the Cataclysmic Star UX UMa

Kjurkchieva, D.; Marchev, D.; Khruzina, T. S.; Djurašević, G.

doi:10.1007/s10509-006-9253-2

Cited by 6 publications

(7 citation statements)

References 30 publications

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“…8). Furthermore, Kjurkchieva et al (2006) employed a spiral arm model to explain the observed features of the light curves of UX UMa from their 9‐yr photometry and the model reproduced well the observational data. Thus, the spiral‐like pattern is apparently a regular structure in the disc of UX UMa.…”

Section: The Accretion Disc and Emission/absorption Structure Of Uxmentioning

confidence: 84%

“…Despite such a rich history of investigations, UX UMa has been almost neglected with optical high‐ or medium‐resolution spectroscopy for the past 25 yr. To our knowledge, no detailed red spectra of UX UMa have been published at all, with the exception of several profiles of the Hα emission‐line (Kjurkchieva et al 2006) and the far‐red spectra in the wavelength range λ λ7661–8308 Å (Vande Putte et al 2003). The latest extensive optical spectroscopic studies of this system in the blue wavelength range have been made by Schlegel, Honeycutt & Kaitchuck (1983).…”

Section: Introductionmentioning

confidence: 99%

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Dark spot, spiral waves and the SW Sextantis behaviour: it is all about UX Ursae Majoris

Neustroev¹,

Suleimanov²,

Borisov³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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We present an analysis of time-resolved, medium-resolution optical spectroscopic observations of UX Ursae Majoris (UX UMa) in the blue (3920-5250 Å) and red (6100-7200 Å) wavelength ranges that were obtained in 1999 April and 2008 March, respectively. The observed characteristics of our spectra indicate that UX UMa has been in different states during those observations. The blue spectra are very complex. They are dominated by strong and broad single-peaked emission lines of hydrogen. The high-excitation lines of He II λ4686 and the Bowen blend are quite strong as well. All the lines consist of a mixture of absorption and emission components. Using Doppler tomography, we have identified four distinct components of the system: the accretion disc, the secondary star, the bright spot from the gas stream/disc impact region and the unique compact area of absorption in the accretion disc seen as a dark spot in the lower left-hand quadrant of the tomograms. In the red wavelength range, both the hydrogen (Hα) and neutral helium (He I λ6678 and He I λ7065) lines were observed in emission and both exhibited double-peaked profiles. Doppler tomography of these lines reveals spiral structure in the accretion disc, but in contrast to the blue wavelength range, there is no evidence for either the dark spot or the gas stream/disc impact region emission, while the emission from the secondary star is weak. During the observations in 1999, UX UMa showed many of the defining properties of the SW Sextantis stars. However, all these features almost completely disappeared in 2008. We have also estimated the radial velocity semi-amplitudes K 1 and K 2 and evaluated the system parameters of UX UMa. These estimates are inconsistent with previous values derived by means of analysis of white dwarf eclipse features in the light curve in different wavelength ranges.

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Section: The Accretion Disc and Emission/absorption Structure Of Uxmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Dark spot, spiral waves and the SW Sextantis behaviour: it is all about UX Ursae Majoris

Neustroev¹,

Suleimanov²,

Borisov³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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“…16 in Kjurkchieva et al 2006); (ii) The α g value of UX UMa is about 0.6, i.e., near to the steady-state value of 0.75, while the α g value of J0107 is about 0.2, which is far from the equilibrium value.…”

Section: The Non-steady Emission Of the Accretion Diskmentioning

confidence: 93%

“…To exhibit them we compared the global characteristics of the newly discovered nova-like star J0107 with those of the well-known novalike eclipsing binary UX UMa whose photometry was fitted with the same model (Kjurkchieva et al 2006;Khruzina et al 2007). …”

Section: The Non-steady Emission Of the Accretion Diskmentioning

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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“…In Figure 7, we compare the Hα profile of EM Cep in its Be state (Figure 7) with those of two other disklike stars, FK Com (Kjurkchieva & Marchev 2005) and the nova-like, cataclysmic star UX UMa (Kjurkchieva et al 2006), observed with the same equipment. We find that all three Hα profiles have very similar widths and emission peak separations.…”

Section: Comparison Of Hα Among Different Types Of Starsmentioning

confidence: 99%

THE B AND Be STATES OF THE STAR EM CEPHEUS

Kjurkchieva¹,

Marchev²,

Sigut³

et al. 2016

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We present 11yrof high-resolution, spectroscopic observations for the star EMCep. EMCep switches between B and Be star states, as revealed by the level of Hα emission, but spends most of its time in the Bstar state. EMCep has been considered to be an eclipsing, near-contact binary of nearly equal-massB stars in order to reproduce regular photometric variations; however, this model is problematic due to the lack of any observed Doppler shift in the spectrum. Our observations confirm that there are no apparent Doppler shifts in the wide spectral lines Hα and He Iλ6678 in either the B or Be star states. The profiles of He Iλ6678 typically exhibited a filled-in absorption core, but we detected weak emission in this line during the highest Be state. Given the lack of observed Doppler shifts, we model EMCep as an isolated Be star with a variable circumstellar disk. We can reproduce the observed Hα emission profiles over the 11yr period reasonably well with disk masses on the order of * -M 3 10 10 11 -in the Be state with the circumstellar disk seen at an inclination of 78°to the line of sight. From a disk ejection episode in 2014, we estimate a mass-loss rate of »´-- M 3 10 yr 91 . The derived disk density parameters are typical of those found for the classical Be stars. We therefore suggest that the EMCep is a classical Be star and that its photometric variations are the result of b Cep or nonradial pulsations.

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Photometric and Hα Observations of the Cataclysmic Star UX UMa

Cited by 6 publications

References 30 publications

Dark spot, spiral waves and the SW Sextantis behaviour: it is all about UX Ursae Majoris

Dark spot, spiral waves and the SW Sextantis behaviour: it is all about UX Ursae Majoris

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

THE B AND Be STATES OF THE STAR EM CEPHEUS

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