Detection of superhumps in the VY Scl-type nova-like variable KR Aur

Kozhevnikov, V. P.

doi:10.1111/j.1365-2966.2007.11819.x

Cited by 18 publications

(17 citation statements)

References 23 publications

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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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Section: The Photometric Periodmentioning

confidence: 99%

Photometry of some more neglected bright cataclysmic variables and candidates

Bruch

2018

New Astronomy

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“…KR Aur is one of six out of 23 VY Scl nova-likes which have negative superhumps. Negative superhumps may arise when a disk becomes tilted due to intense radiation from a very hot white dwarf and thus could be an indirect indicator of nuclear burning (Kozhevnikov 2007). The other systems with negative superhumps are V442 Oph, DW UMa, TT Ari and V751 Cyg.…”

Section: Kr Aurmentioning

confidence: 99%

Far Ultraviolet Spectroscopy of Seven Nova-Like Variables

Mizusawa

Merritt

Ballouz

et al. 2010

PUBL ASTRON SOC PAC

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ABSTRACT. We present the results of a multicomponent synthetic spectral analysis of the archival far ultraviolet spectra of several key nova-like variables including members of the SW Sex, RW Tri, UX UMa, and VY Scl subclasses: KR Aur, RW Tri, V825 Her, V795 Her, BP Lyn, V425 Cas, and HL Aqr. Accretion rates as well as the possible flux contribution of the accreting white dwarf are included in our analysis. Except for RW Tri, which has a reliable trigonometric parallax, we computed the distances to the nova-like systems using the method of Knigge. Our analysis of seven archival IUE spectra of RW Tri at its parallax distance of 341 pc consistently indicates a low mass (∼0:4 M ⊙ ) white dwarf and an average accretion rate, _ M ¼ 6:3 × 10 À9 M ⊙ yr À1 . For KR Aur, we estimate that the white dwarf has T eff ¼ 29; 000 AE 2000 K, log g ¼ 8:4, and contributes 18% of the far-UV flux, while an accretion disk with accretion rate _ M ¼ 3 × 10 À10 M ⊙ yr À1 at an inclination of 41°contributes the remainder. We find that an accretion disk dominates the far-UV spectrum of V425 Cas but a white dwarf contributes nonnegligibly with approximately 18% of the far-UV flux. For the two high state nova-likes, HL Aqr and V825 Her, their accretion disks totally dominate with _ M ¼ 1 × 10 À9 M ⊙ yr À1 and 3 × 10 À9 M ⊙ yr À1 , respectively. For BP Lyn we find _ M ¼ 1 × 10 À8 M ⊙ yr À1 while for V795 Her, we find an accretion rate of _ M ¼ 1 × 10 À10 M ⊙ yr À1 . We discuss the implications of our results for the evolutionary status of nova-like variables.

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“…Besides the SU UMa type of CVs, some of the VY Scl type of CVs (or anti-dwarf novae), a subtype of nova-like (NL) CV, were detected to have superhump signals. For example, Kozhevnikov (2007) discovered a negative superhump P sh = 3.771 ± 0.005 h in KR Aur, a VY Scl NL CV. In addition to the SU UMa and NL systems, superhumps were also observed in the intermediate polar (IP, or DQ Her type of CVs).…”

Section: Precession Of Accretion Diskmentioning

confidence: 99%

Long-term Periodicities of Cataclysmic Variables with Synoptic Surveys

Yang

Chou

Ngeow

et al. 2017

PASP

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A systematic study on the long-term periodicities of known Galactic cataclysmic variables (CVs) was conducted. Among 1580 known CVs, 344 sources were matched and extracted from the Palomar Transient Factory (PTF) data repository. The PTF light curves were combined with the Catalina Real-Time Transient Survey (CRTS) light curves and analyzed. Ten targets were found to exhibit long-term periodic variability, which is not frequently observed in the CV systems. These longterm variations are possibly caused by various mechanisms, such as the precession of the accretion disk, hierarchical triple star system, magnetic field change of the companion star, and other possible mechanisms. We discuss the possible mechanisms in this study. If the long-term period is less than several tens of days, the disk precession period scenario is favored. However, the hierarchical triple Long-term Periodicities of CVs with Synoptic Surveys YANG, Michael T.C. et al.days, likely caused by the modulation of the mass-transfer rate owing to the magnetic cycles in the companion stars.Previous studies on the long-term periodicities of CVs are sporadic. With the help of recent large synoptic surveys, we are able to search for and further characterize the long-term variations of the CVs systematically. In Section 2, we introduce the synoptic survey projects we utilized, and the corresponding intensive observations made using the Lulin One-Meter-Telescope (LOT).Descriptions of our analysis method for the long-term periodicity of the sources are presented in Section 3. The possible mechanisms driving the long-term variability and further implications are presented in Section 4. In Section 5, we summarize the long-term periodicities from our results and discuss some of the previous studies related to the sources.

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Detection of superhumps in the VY Scl-type nova-like variable KR Aur

Cited by 18 publications

References 23 publications

Photometry of some more neglected bright cataclysmic variables and candidates

Photometry of some more neglected bright cataclysmic variables and candidates

Far Ultraviolet Spectroscopy of Seven Nova-Like Variables

Long-term Periodicities of Cataclysmic Variables with Synoptic Surveys

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