Grazing Eclipsing Dwarf Nova CW Monocerotis: Dwarf Nova-Type Outburst in a Possible Intermediate Polar?

Katô, Takeo; Uemura, Makoto; Kiyota, S.; Tanabe, Kenji; Koizumi, M.; Kida, Mayumi; Nishi, Yuichi; Tanaka, Sawa; Ueoka, Rie; Yasui, Hideki; Vanmunster, Tonny; Nogami, Daisaku; Yamaoka, H.

doi:10.1093/pasj/55.2.489

Cited by 6 publications

(2 citation statements)

References 86 publications

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“…CW Mon is a typical DNe with an orbital period of 4.238 hr, and exhibits grazing eclipses (Kato et al 2003). CW Mon has a significant X-ray luminosity (Verbunt et al 1997), suggesting that it might be an IP.…”

Section: Cw Monocerotismentioning

confidence: 99%

Abundance Derivations for the Secondary Stars in Cataclysmic Variables From Near-Infrared Spectroscopy

Harrison

2016

ApJ

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We derive metallicities for 41 cataclysmic variables (CVs) from near-infrared spectroscopy. We use synthetic spectra that cover the 0.8 µm ≤ λ ≤ 2.5 µm bandpass to ascertain the value of [Fe/H] for CVs with K-type donors, while also deriving abundances for other elements. Using calibrations for determining [Fe/H] from the K-band spectra of M-dwarfs, we derive more precise values for T eff for the secondaries in the shortest period CVs, and examine whether they have carbon deficits. In general, the donor stars in CVs have sub-solar metallicities. We confirm carbon deficits for a large number of systems. CVs with orbital periods > 5 hr are most likely to have unusual abundances. We identify four CVs with CO emission. We use phase-resolved spectra to ascertain the mass and radius of the donor in U Gem. The secondary star in U Gem appears to have a lower apparent gravity than a main sequence star of its spectral type.Applying this result to other CVs, we find that the later-than-expected spectral types observed for many CV donors is mostly an affect of inclination. All of the magnetic CVs, except the low accretion rate polar MQ Dra, have donors with subsolar metallicities. We find that two systems with unusual spectra, EI Psc and QZ Ser, that have large excesses of sodium, and extreme deficits of carbon.Synthetic spectra that have a reduced abundance of hydrogen are best able to explain the spectra of these two objects. The observed dearth of CVs with 2 hr ≤ P orb ≤ 3 hr (see Kolb et al. 1998).unpublished data is presented in Table 1, and it lists the UT date, start and stop times, the length of the exposure times used for each object, the instrument used, the orbital period, the orbital phase at the mid-point of the observational sequence (except for U Gem where full orbits were covered), and the outburst state for each of the CVs.We also present previously unpublished spectra obtained with NIRSPEC 2 on Keck.We used NIRSPEC in low-resolution, single order mode with a 0.38" slit. The grating tilt was set so as to cover the wavelength region 2.04 µm ≤ λ ≤ 2.46 µm, with a dispersion of 4.27Å/pixel. We employed the two-nod script, and used 4 minute exposure times for all of the program CVs. To correct for telluric absorption, we observed bright A0V stars located close to the program objects so as to minimize their relative differences in air mass. These data were reduced using the IDL routine REDSPEC 3 , specially developed for NIRSPEC.Finally, we used TripleSpec 4 (Wilson et al. 2004) on the Apache Point Observatory (APO) 3.5 m telescope to obtain phase-resolved near-IR spectra of U Gem over two orbital periods, and for 50% orbital period coverage of QZ Ser. TripleSpec is similar to SPEX in that it provides cross-dispersed spectra covering the near-IR, from 0.95 µm to 2.46 µm, at a resolution of R ∼ 3500. The 1.1" slit was used, and all exposures were four minutes in length. These data were reduced using "Triplespectool," a version of SPEXTOOL modified by Michael Cushing for use at APO. Nearby A0V stars were used to pr...

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Section: Cw Monocerotismentioning

confidence: 99%

Abundance Derivations for the Secondary Stars in Cataclysmic Variables From Near-Infrared Spectroscopy

Harrison

2016

ApJ

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“…This model can also be used to explain a symmetrical CV eclipse profiles during outburst (e.g. Kato et al 2003;Bakowska & Olech 2015), which is caused by the significant flux increase of the disk (i.e., the luminous accretion disk almost overwhelms the relatively faint white dwarf and hotspot).…”

Section: Introductionmentioning

confidence: 99%

A Phenomenological Model for the Light Curve of Three Quiescent Low-inclination Dwarf Novae and One Pre-cataclysmic Variable

Dai

Szkody

Kennedy

et al. 2018

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We used the light curve code XRBinary to model the quiescent K2 light curves of three low-inclination cataclysmic variables (CVs): 1RXS J0632+2536 (J0632+2536), RZ Leo, TW Vir and the pre-CV WD 1144+011. Optimized light curve models were obtained using a nonlinear fitting code NMfit and visualized by Phoebe 2.0. The disk model of J0632+2536 shows that one hotspot at the edge of the disk is enough to describe its light curve, while the other two dwarf nova (DN): RZ Leo and TW Vir require two hotspots. A typical pre-CV model with a weak irradiation effect for WD 1144+011 can explain its single-hump modulation, and the newly observed spectrum confirms its previous classification. The synthetic analyses for the DN clearly indicate that phase zero of the double-hump modulations occurs around the secondary minimum and the primary hump is mainly caused by the hotspot at the edge of the disk. The quiescent disk has a flat temperature distribution with a power index of ∼ 0.11. The disk model of RZ Leo implies a truncated disk, supporting its previously speculated classification as an intermediate polar (IP). Except for the IP model of RZ Leo, which lacks a component related to the inferred accretion curtain, the models of J0632+2536, TW Vir and WD 1144+011 are consistent with results from the Gaia mission. TheCorresponding author: Zhibin Dai zhibin dai@ynao.ac.cn arXiv:1808.06174v1 [astro-ph.SR] 19 Aug 2018 2 derived masses and radii of the secondaries of the three DN are consistent with the semiempirical relations for CV donor stars, while their effective temperatures are higher than the predictions. Irradiation of the donor stars is investigated to explain this discrepancy.

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Rapid Oscillations in Cataclysmic Variables

Warner

2004

PUBL ASTRON SOC PAC

105

119

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I give an overview of the rich phenomenology of dwarf nova oscillations (DNOs) and Quasi-periodic Oscillations (QPOs) observed in cataclysmic variable stars (CVs). The favoured interpretation of these rapid brightness modulations (3 - >1000 s time scales) is that they are magnetic in nature - magnetically channelled accretion from the inner accretion disc for DNOs and possible magnetically excited travelling waves in the disc for QPOs. There is increasing evidence for the magnetic aspects, which extend to lower field the well known properties of strong field (polars) and intermediate strength field (intermediate polars) CVs. The result is that almost all CVs show the presence of magnetic fields on their white dwarf primaries - though for many the intrinsic field may be locally enhanced by the accretion process itself. There are many parallel behaviours with the QPOs seen in X-Ray binaries, with high and low frequency X-Ray QPOs resembling respectively the DNOs and QPOs in CVs.Comment: Invited Review for PASP, accepted for publication in the February 2004 issue of PAS

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Grazing Eclipsing Dwarf Nova CW Monocerotis: Dwarf Nova-Type Outburst in a Possible Intermediate Polar?

Cited by 6 publications

References 86 publications

Abundance Derivations for the Secondary Stars in Cataclysmic Variables From Near-Infrared Spectroscopy

Abundance Derivations for the Secondary Stars in Cataclysmic Variables From Near-Infrared Spectroscopy

A Phenomenological Model for the Light Curve of Three Quiescent Low-inclination Dwarf Novae and One Pre-cataclysmic Variable

Rapid Oscillations in Cataclysmic Variables

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