Decrease in the orbital period of dwarf nova OY Carinae

Greenhill, J.; Hill, K. M.; Dieters, S.; Fienberg, Kurt; Howlett, M.; Meijers, A.J.S.; Munro, Angus; Senkbeil, C.

doi:10.1111/j.1365-2966.2006.10920.x

Cited by 15 publications

(14 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The decrease from the period given in Greenhill et al (2006) has been confirmed. The rate of secular decrease was about a half (−0.7 × 10 −13 ) of that reported in Greenhill et al (2006).…”

Section: Oy Carinaesupporting

confidence: 62%

Survey of period variations of superhumps in SU UMa-type dwarf novae. VII. The seventh year (2014–2015)

Katô

Hambsch

Dubovský

et al. 2015

Publications of the Astronomical Society of Japan

View full text Add to dashboard Cite

Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 102 SU UMa-type dwarf novae, observed mainly during the 2014-2015 season, and characterized these objects. Our project has greatly improved the statistics of the distribution of orbital periods, which is a good approximation of the distribution of cataclysmic variables at the terminal evolutionary stage, and has confirmed the presence of a period minimum at a period of 0.053 d and a period spike just above this period. The number density monotonically decreased toward the longer period and there was no strong indication of a period gap. We detected possible negative superhumps in Z Cha. It is possible that normal outbursts are also suppressed by the presence of a disk tilt in this system. There was no indication of enhanced orbital humps just preceding the superoutburst, and this result favors the thermal-tidal disk instability as the origin of superoutbursts. We detected superhumps in three AM CVn-type dwarf novae. Our observations and recent other detections suggest that 8% of objects showing dwarf nova-type outbursts are AM CVn-type objects. AM CVn-type objects and EI Psc-type objects may be more abundant than previously recognized. OT J213806, a WZ Sge-type object, exhibited remarkably different features between the 2010 and 2014 superoutbursts. Although the 2014 superoutburst was much fainter, the plateau phase was shorter than the 2010 one, and the course of the rebrightening phase was similar. This object indicates that the O − C diagrams of superhumps can indeed be variable, at least in WZ Sge-type objects. Four deeply eclipsing SU UMa-type dwarf novae (ASASSN-13cx, ASASSN-14ag, ASASSN15bu, and NSV 4618) were identified. We studied long-term trends in supercycles in MM Hya and CY UMa and found systematic variations of supercycles of ∼20%.

show abstract

Section: Oy Carinaesupporting

confidence: 62%

Survey of period variations of superhumps in SU UMa-type dwarf novae. VII. The seventh year (2014–2015)

Katô

Hambsch

Dubovský

et al. 2015

Publications of the Astronomical Society of Japan

View full text Add to dashboard Cite

show abstract

“…The zero‐point for the orbital phase was a free parameter in these fits, and we find it to be at HJD 244 3993.548 92(4). We used the orbital period from the quadratic ephemeris given in Greenhill et al (2006). We give the results for each line fitted individually with a single Gaussian model, as well as a combined fit in which the four lines are fitted together with a common γ, K 2 and velocity width.…”

Section: Resultsmentioning

confidence: 99%

A J-band detection of the donor star in the dwarf nova OY Carinae and an optical detection of its ‘iron curtain’

Copperwheat

Marsh

Parsons

et al. 2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Purely photometric models can be used to determine the binary parameters of eclipsing cataclysmic variables (CVs) with a high degree of precision. However, the photometric method relies on a number of assumptions, and to date there have been very few independent checks of this method in the literature. We present time‐resolved spectroscopy of the P= 90.9 min eclipsing CV OY Carinae obtained with X‐shooter on the Very Large Telescope (VLT), in which we detect the donor star from K i lines in the J band. We measure the radial velocity amplitude of the donor star K2= 470.0 ± 2.7 km s−1, consistent with predictions based upon the photometric method (470 ± 7 km s−1). Additionally, the spectra obtained in the UVB arm of X‐shooter show a series of Fe i and Fe ii lines with a phase and velocity consistent with an origin in the accretion disc. This is the first unambiguous detection at optical wavelengths of the ‘iron curtain’ of disc material which has been previously reported to veil the white dwarf in this system. The velocities of these lines do not track the white dwarf, reflecting a distortion of the outer disc that we see also in Doppler images. This is evidence for considerable radial motion in the outer disc, at up to 90 km s−1 towards and away from the white dwarf.

show abstract

“…Such a strong angular momentum loss for a system below the period gap would clearly violate the standard evolutionary scenario of disrupted magnetic braking. Notably, a period decrease at a similar level was recently detected in three other short period binaries: DP Leo (Schwope et al 2002), NN Ser (Brinkworth et al 2006) and OY Car (Greenhill et al 2006). Future observations have to show if these variations are indeed secular or if their periodic nature is masked by the yet insufficient baseline.…”

Section: Discussionmentioning

confidence: 97%

Hunting high and low: XMM monitoring of the eclipsing polar HU Aquarii

Schwarz¹,

Schwope²,

Vogel³

et al. 2009

A&A

View full text Add to dashboard Cite

Aims. We want to study the temporal and spectral behaviour of HU Aqr in the X-ray domain during different accretion states. Methods. We obtained spectra and light curves from four different XMM-Newton pointings covering intermediate and low states. The X-ray observations were accompanied with high time resolution photometry obtained with the Optima and ULTRACAM instruments. Results. On two occasions in May 2002 and 2003 HU Aqr was found in an intermediate state with the accretion rate reduced by a factor of 50 compared to earlier high state measurements. X-ray spectra in the intermediate state can be described by a model containing a blackbody component and hot thermal plasma. Contrary to the high state the ratio between soft and hard X-ray flux is nearly balanced. In agreement with previous measurements we observed a migration of the accretion spot and stream towards the line connecting both stars. The brightness of HU Aqr was further reduced by a factor of 80 during two low states in October 2003 and May 2005, where it was detected at a luminosity of only L X = 4.7 × 10 28 erg s −1 . This luminosity would fit well with an active coronal emitter, but the relatively high plasma temperatures of 3.5 and 2.0 keV are more compatible with residual accretion. We updated the eclipse ephemeris of HU Aqr based on the eclipse egress of the accretion spot measured in various wavelength bands. The (O−C)-diagram of the observed accretion spot eclipse timings reveals complex deviations from a linear trend, which can be explained by a constant or cyclic period change or a combination thereof. The quadratic term implies a period decrease at a rate oḟ P orb = −7.. − 11 × 10 −12 s s −1 . In case the observed period change reflects a true angular momentum loss, this would be a factor of 30 larger than given by gravitational radiation.

show abstract

Decrease in the orbital period of dwarf nova OY Carinae

Cited by 15 publications

References 11 publications

Survey of period variations of superhumps in SU UMa-type dwarf novae. VII. The seventh year (2014–2015)

Survey of period variations of superhumps in SU UMa-type dwarf novae. VII. The seventh year (2014–2015)

A J-band detection of the donor star in the dwarf nova OY Carinae and an optical detection of its ‘iron curtain’

Hunting high and low: XMM monitoring of the eclipsing polar HU Aquarii

Contact Info

Product

Resources

About