KIC 9406652: A laboratory of the tilted disk in cataclysmic variable stars

Abstract

KIC 9406652 is a cataclysmic variable (CV), sub-classified as `IW And-type star', showing a repetition of standstills with oscillatory variations terminated by brightening. This system showed negative superhumps, semi-periodic variations having periods slightly shorter than the orbital period, and super-orbital signals, both of which are believed to originate from a precessing, tilted accretion disk. We have re-examined its Kepler light curve extending over 1500 d. In accordance with a cycle of the IW And-type light variation, the frequency of negative superhumps showed a reproducible variation: a rapid drop during the brightening and a gradual increase during the standstill. They are interpreted as the drastic change in the radial mass distribution and the expansion of the tilted disk, which is not expected from the existing models for IW And stars. The constancy in flux amplitudes of negative superhumps confirms that their light source is the bright spot sweeping across the surface of the tilted disk. The frequencies of negative superhumps and super-orbital signals varied in unison on long timescales, suggesting their common origin: the tilted disk. Orbital signals at the brightening were dominated by the irradiation of the secondary star and varied with the orientation of the tilted disk; the amplitude was maximized at the minimum of super-orbital signals and the light maximum shifted to early orbital phases as the super-orbital phase advances. This is the first direct evidence that the disk was tilted out of the binary orbital plane and retrogradely precessing. The tilt angle of the disk inferred from semi-amplitudes of super-orbital signals was lower than 3 degrees. The diversity in light curves of negative superhumps supports this and suggests that a part of the gas stream overflows the disk edge. This study thus offers rich information about the tilted disk in CVs.

arXiv commentAccepted for publication in PASJ. 17 pages and 14 figures (The previous version has some problems in converting the manuscript to a PDF)

References in corpus (18)

• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae
• Recurrent novae as a progenitor system of Type Ia supernovae. I. RS Ophiuchi subclass --- Systems with a red giant companion
• On the precession of accretion discs in X-ray binaries
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. II: The Second Year (2009-2010)
• Hydrodynamics of the stream-disk impact in interacting binaries
• An examination of some characteristics of Kepler Short and Long Cadence Data
• Study of Superoutbursts and Superhumps in SU UMa Stars by the Kepler Light Curves of V344 Lyrae and V1504 Cygni
• Smoothed Particle Hydrodynamics Simulations of Apsidal and Nodal Superhumps
• A Further Study of Superoutbursts and Superhumps in SU UMa Stars by the Kepler Light Curves of V1504 Cygni and V344 Lyrae
• Orbital, Superhump, and Superorbital Periods in the Cataclysmic Variables AQ Mensae and IM Eridani
• Magnetically warped discs in close binaries
• KIC 9406652: An Unusual Cataclysmic Variable in the Kepler Field of View
• A Study of the Unusual Z Cam Systems IW Andromedae and V513 Cassiopeia
• Anomalous Z Cam stars: a response to mass-transfer outbursts
• A molecular line survey toward the nearby galaxies NGC 1068, NGC 253, and IC 342 at 3 mm with the Nobeyama 45 m radio telescope: The data
• Thermal-viscous instability in tilted accretion disks: a possible application to IW And-type dwarf novae
• Discovery of Standstills in the SU UMa-Type Dwarf Nova NY Serpentis
• IW And-Type State in IM Eridani

Cited by in corpus (13)

• TESS light curves of cataclysmic variables -- II: Superhumps in old novae and novalike variables
• New evidence for the precession of tilted disk in SDSS J081256.85+191157.8
• BO Ceti: Dwarf Nova Showing Both IW And and SU UMa-Type Features
• Nine New Cataclysmic Variable Stars with Negative Superhumps
• On the nature of the anomalous event in 2021 in the dwarf nova SS Cygni and its multi-wavelength transition
• Tilted discs in six poorly studied cataclysmic variables
• Evolution of negative superhumps, quasi-periodic oscillations and outbursts in the Z Cam-type dwarf nova AH Her
• KIC 9406652: A laboratory for tilted disks in cataclysmic variable stars. II. Modeling of the orbital light curves
• HO Puppis: Not a Be Star but a Newly Confirmed IW And-Type Star
• Tilted Disk Precession and Negative Superhumps in HS 2325+8205: A Multi-Window Analysis
• Superhumps in the cataclysmic variable BG Tri
• A New IW And-Type Star: Karachurin 12 with Tilted Disks and Diverse cycles
• The light curve simulations of the 2021 anomalous event in SS Cygni