HS 0139+0559, HS 0229+8016, HS 0506+7725, and HS 0642+5049: four new long-period cataclysmic variables

Aungwerojwit, A.; Gänsicke, B. T.; Rodríguez‐Gil, P.; Hagen, H. J.; Harlaftis, E. T.; Papadimitriou, Christos; Lehto, H. J.; Araujo-Betancor, S.; Heber, U.; Fried, Robert; Engels, D.; Katajainen, S.

doi:10.1051/0004-6361:20042610

Cited by 33 publications

(28 citation statements)

References 37 publications

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“…18 (top panel). The first thing to notice is that the majority of the new CVs identified in the HQS are found above the period gap, with a large number of systems in the period range 3−4 h (for a discussion of the properties of CVs in this period range, see Aungwerojwit et al 2005). As for the overall CV population, a dearth of systems is observed in the 2−3 h period range (Fig.…”

Section: The Orbital Period Distribution Of Dwarf Novae In the Hqsmentioning

confidence: 95%

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Dwarf novae in the Hamburg quasar survey: rarer than expected

Aungwerojwit¹,

Gänsicke²,

Rodríguez‐Gil

et al. 2006

A&A

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Aims. We report the discovery of five new dwarf novae that were spectroscopically identified in the Hamburg Quasar Survey (HQS), and discuss the properties of the sample of new dwarf novae from the HQS. Methods. Follow-up time-resolved spectroscopy and photometry have been obtained to characterise the new systems. Results. The orbital periods determined from analyses of the radial velocity variations and/or orbital photometric variability are P orb 105.1 min or P orb 109.9 min for HS 0417+7445, P orb = 114.3 ± 2.7 min for HS 1016+3412, P orb = 92.66 ± 0.17 min for HS 1340+1524, P orb = 272.317 ± 0.001 min for HS 1857+7127, and P orb = 258.02 ± 0.56 min for HS 2214+2845. HS 1857+7127 is found to be partially eclipsing. In HS 2214+2845 the secondary star of spectral type M3 ± 1 is clearly detected, and we estimate the distance to the system to be d = 390 ± 40 pc. We recorded one superoutburst of HS 0417+7445, identifying the system as a SU UMatype dwarf nova. HS 1016+3412 and HS 1340+1524 have rare outbursts, and their subtype is yet undetermined. HS 1857+7127 frequently varies in brightness and may be a Z Cam-type dwarf nova. HS 2214+2845 is a U Gem-type dwarf nova with a most likely cycle length of 71 d. Conclusions. To date, 14 new dwarf novae have been identified in the HQS. The ratio of short-period (<3 h) to long-period (>3 h) systems of this sample is 1.3, much smaller compared to the ratio of 2.7 found for all known dwarf novae. The HQS dwarf novae display typically infrequent or low-amplitude outburst activity, underlining the strength of spectroscopic selection in identifying new CVs independently of their variability. The spectroscopic properties of short-period CVs in the HQS, newly identified and previously known, suggest that most, or possibly all of them are still evolving towards the minimum period. Their total number agrees with the predictions of population models within an order of magnitude. However, the bulk of all CVs is predicted to have evolved past the minimum period, and those systems remain unidentified. This suggests that those post-bounce systems have markedly weaker Hβ emission lines compared to the average known short-period CVs, and undergo no or extremely rare outbursts.

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Section: The Orbital Period Distribution Of Dwarf Novae In the Hqsmentioning

confidence: 95%

“…The survey resulted in 50 new CVs, including a number of peculiar objects (e.g. Gänsicke et al 2000;Rodríguez-Gil et al 2004bAraujo-Betancor et al 2005a); a general overview has been given by Gänsicke et al (2002) and more recently by Aungwerojwit et al (2005).…”

Section: Introductionmentioning

confidence: 99%

Dwarf novae in the Hamburg quasar survey: rarer than expected

Aungwerojwit¹,

Gänsicke²,

Rodríguez‐Gil

et al. 2006

A&A

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“…Disagreements between the observational and theoretical studies of CV populations could be often attributed to the incompleteness of surveys, which are mostly due to unavoidable selection effects of observational data (Della Valle & Livio, 1996;Aungwerojwit et al, 2005;Gänsicke, 2005;Pretorius, Knigge & Kolb, 2007). Indeed, one of the goals of CV surveys is to reduce the selection effects by observing the fainter CVs and thereby provide a more accurate picture of the actual CV population since the theory predicts the most of CVs should be intrinsically faint (Howell, Rappaport & Politano, 1997;Kolb, 2001).…”

Section: Completeness Of the Samplementioning

confidence: 99%

“…Standard models for the population of CVs predict a galactic space density of 10 −5 −10 −4 pc −3 (Ritter & Burkert, 1986;de Kool, 1992;Politano, 1996;Kolb, 2001;Willems et al, 2005Willems et al, , 2006. These predictions are inconsistent with the observed space densities of ∼10 −6 −10 −5 pc −3 (Warner, 1974;Patterson, 1984Patterson, , 1998Ringwald, 1993;Schwope et al, 2002;Aungwerojwit et al, 2005;Araujo-Betancor et al, 2005;Grindlay et al, 2005).…”

Section: Introductionmentioning

confidence: 98%

Spatial distribution and galactic model parameters of cataclysmic variables

Bilir

et al. 2008

New Astronomy

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The spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been determined from a carefully established sample of 459 CVs. The sample contains all of the CVs with distances computed from the Period-Luminosity-Colours (PLCs) relation of CVs which has been recently derived and calibrated with 2MASS photometric data. It has been found that an exponential function fits best to the observational zdistributions of all of the CVs in the sample, non-magnetic CVs and dwarf novae, while the sech 2 function is more appropriate for nova-like stars and polars. The vertical scaleheight of CVs is 158±14 pc for the 2MASS J-band limiting apparent magnitude of 15.8. On the other hand, the vertical scaleheights are 128±20 and 160±5 pc for dwarf novae and nova-like stars, respectively. The local space density of CVs is found to be ∼ 3 × 10 −5 pc −3 which is in agreement with the lower limit of the theoretical predictions. The luminosity function of CVs shows an increasing trend toward higher space densities at low luminosities, implying that the number of short-period systems should be high. The discrepancies between the theoretical and observational population studies of CVs will almost disappear if for the zdependence of the space density the sech 2 density function is used.

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“…Article published by EDP Sciences magnetic CVs with relatively weak X-ray emission such as 1RXS J062518.2+733433 (HS 0618+7336, Araujo-Betancor et al 2003), RX J1554.2+2721 (HS 1552+2730, Thorstensen & Fenton 2002;Gänsicke et al 2004), and HS 0943+1404 ); a number of SW Sextantis stars (Szkody et al 2001;Rodríguez-Gil et al 2004; one of the youngest pre-CVs known (HS 1857+5144, Aungwerojwit et al 2007); long-period CVs (Aungwerojwit et al 2005); and several dwarf novae (Aungwerojwit et al 2006). This paper presents the dynamical determination of the stellar masses in the cataclysmic variable HS 0218+3229.…”

Section: Introductionmentioning

confidence: 99%

An evolved donor star in the long-period cataclysmic variable HS 0218+3229

Rodríguez‐Gil

Torres

Gänsicke

et al. 2009

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Context. We present time-resolved spectroscopy and photometry of HS 0218+3229, a new long-period cataclysmic variable discovered within the Hamburg Quasar Survey. It is one of the few systems that allow a dynamical measurement of the masses of the stellar components. Aims. We combine the analysis of time-resolved optical spectroscopy and R-band photometry with the aim of measuring the mass of the white dwarf and the donor star and the orbital inclination. Methods. Cross-correlation of the spectra with K-type dwarf templates is used to derive the radial velocity curve of the donor star. An optimal subtraction of the broadened templates is performed to measure the rotational broadening and constrain the spectral type of the donor. Finally, an ellipsoidal model is fitted to the R-band light curve to obtain constraints upon the orbital inclination of the binary system. Results. The orbital period of HS 0218+3229 is found to be 0.297229661 ± 0.000000001 d (7.13351186 ± 0.00000002 h), and the amplitude of the donor's radial velocity curve is K 2 = 162.4 ± 1.4 km s −1 . Modelling the ellipsoidal light curves gives an orbital inclination in the range i = 59 • ± 3 • . A rotational broadening between 82.4 ± 1.2 km s −1 and 89.4 ± 1.3 km s −1 is found when assuming zero and continuum limb darkening, respectively. The secondary star has most likely a spectral type K5 and contributes ∼80-85% to the R-band light. Our analysis yields a mass ratio of 0.52 < q < 0.65, a white dwarf mass of 0.44 < M 1 (M ) < 0.65, and a donor star mass of 0.23 < M 2 (M ) < 0.44. Conclusions. We find that the donor star in HS 0218+3229 is significantly undermassive for its spectral type. It is therefore very likely that it has undergone nuclear evolution prior to the onset of mass transfer.

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HS 0139+0559, HS 0229+8016, HS 0506+7725, and HS 0642+5049: four new long-period cataclysmic variables

Cited by 33 publications

References 37 publications

Dwarf novae in the Hamburg quasar survey: rarer than expected

Dwarf novae in the Hamburg quasar survey: rarer than expected

Spatial distribution and galactic model parameters of cataclysmic variables

An evolved donor star in the long-period cataclysmic variable HS 0218+3229

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