Search for magnetic accretion in SW Sextantis systems

Abstract

SW Sextantis systems are nova-like cataclysmic variables that have unusual spectroscopic properties, which are thought to be caused by an accretion geometry having part of the mass flux trajectory out of the orbital plane. Accretion onto a magnetic white dwarf is one of the proposed scenarios for these systems. To verify this possibility, we analysed photometric and polarimetric time-series data for a sample of six SW Sex stars. We report possible modulated circular polarization in BO Cet, SW Sex, and UU Aqr with periods of 11.1, 41.2 and 25.7 min, respectively, and less significant periodicities for V380 Oph at 22 min and V442 Oph at 19.4 min. We confirm previous results that LS Peg shows variable circular polarization. However, we determine a period of 18.8 min, which is different from the earlier reported value. We interpret these periods as the spin periods of the white dwarfs. Our polarimetric results indicate that 15% of the SW Sex systems have direct evidence of magnetic accretion. We also discuss SW Sex objects within the perspective of being magnetic systems, considering the latest findings about cataclysmic variables demography, formation and evolution.

arXiv comment29 pages, 17 figures

References in corpus (69)

• The USNO-B Catalog
• Catalogue of cataclysmic binaries, low-mass X-ray binaries and related objects (Seventh edition)
• The Evolution of Cataclysmic Variables as Revealed by their Donor Stars
• X-ray Emissions from Accreting White Dwarfs: a Review
• Post-common-envelope binaries from SDSS. XI: The white dwarf mass distributions of CVs and pre-CVs
• Superhumps in Cataclysmic Binaries. XXV. q_crit, epsilon(q), and Mass-Radius
• Photometric Variability in Kepler Target Stars. II. An Overview of Amplitude, Periodicity, and Rotation in First Quarter Data
• Placing Confidence Limits on Polarization Measurements
• First science with SALT: peering at the accreting polar caps of the eclipsing polar SDSS J015543.40+002807.2
• A Volume Limited Sample of Cataclysmic Variables from $Gaia$ DR2: Space Density and Population Properties
• The complete set of ASCA X-ray observations of non-magnetic cataclysmic variables
• Three in one go: consequential angular momentum loss can solve major problems of CV evolution
• The Most Magnetic Stars
• A common origin of magnetism from planets to white dwarfs
• Effective Temperatures of Cataclysmic Variable White Dwarfs as a Probe of their Evolution
• SW Sextantis stars: the dominant population of CVs with orbital periods between 3-4 hours
• The evolutionary status of Cataclysmic Variables: Eclipse modelling of 15 systems
• Evidence for reduced magnetic braking in polars from binary population models
• The Accretion Flows and Evolution of Magnetic Cataclysmic Variables
• The mass of the white dwarf in the old nova BT Mon
• Superhumps in Cataclysmic Binaries. XXIII. V442 Ophiuchi and RX J1643.7+3402
• Evidence of magnetic accretion in an SW Sex star: discovery of variable circular polarization in LS Pegasi
• The formation of Cataclysmic Variables: the influence of nova eruptions
• Detached cataclysmic variables are crossing the orbital period gap
• MOCCA-SURVEY database I. Accreting white dwarf binary systems in globular clusters -- IV. cataclysmic variables -- properties of bright and faint populations
• Spectroscopic search for new SW Sextantis stars in the 3-4 hour orbital period range -- I
• Observations of the SW Sextantis star DW Ursae Majoris with the Far Ultraviolet Spectroscopic Explorer
• LS Peg: A Low-Inclination SW Sextantis-Type Cataclysmic Binary with High-Velocity Balmer Emission Line Wings
• Stellar Cycles from Photometric Data: CoRoT Stars
• Outbursts of EX Hydrae: mass-transfer events or disc instabilities?
• The defining characteristics of Intermediate Polars - the case of three candidate systems
• SW Sextantis in an excited, low state
• Magnetic white dwarfs in post-common-envelope binaries
• Genesis of magnetic fields in isolated white dwarfs
• Circular polarization survey of intermediate polars I. Northern targets in the range 17h<R.A.<23h
• The SW Sex enigma
• The origin of single low-mass WDs: another problem that consequential angular momentum loss in CVs might solve
• On the space density of X-ray selected cataclysmic variables
• Doppler tomography of intermediate polar spin cycles
• V405 Aurigae: A High Magnetic Field Intermediate Polar
• Short Term Variability of Evolved Massive Stars with TESS II: A New Class of Cool, Pulsating Supergiants
• An XMM-Newton observation of the nova-like variable UX UMa: spatially and spectrally resolved two-component X-ray emission
• Are white dwarf magnetic fields in close binaries generated during common-envelope evolution?
• A two-armed pattern in flickering maps of the nova-like variable UU Aquarii
• XMM-Newton observations of eleven intermediate polars and possible candidates
• Observations of the SW Sextantis Star UU Aquarii
• On the spin modulated circular polarization from the intermediate polars NY Lup and IGRJ1509-6649
• Spin-resolved spectroscopy of the intermediate polar DQ Her
• On the SW Sex-Type Eclipsing Cataclysmic Variable SDSS0756+0858
• The Nova-like Variables
• The magnetic SW Sextantis star RX J1643.7+3402
• When the disc's away, the stars will play: dynamical masses in the nova-like variable KR Aur with a pinch of accretion
• Characterizing Three Candidate Magnetic CVs from SDSS: XMM-Newton and Optical Follow-up Observations
• On The Accretion Rates of SW Sextantis Nova-Like Variables
• Hubble Space Telescope STIS Spectroscopy of Three Peculiar Nova-Like Variables: BK Lyn, V751 Cygni and V380 Oph
• Stokes imaging of AM Her systems using 3D inhomogeneous models-II. Modelling X-ray and optical data of CP Tucanae
• On the White Dwarf Mass Problem of Cataclysmic Variables
• Discovery of a bright eclipsing cataclysmic variable
• Life after eruption VIII: The orbital periods of novae
• Followup Observations of SDSS and CRTS Candidate Cataclysmic Variables II
• New Insights into Time Series Analysis III - Setting constraints on period analysis
• Discovery of variable circular polarization from the remnant of Nova Chamaeleontis 1953 (RR Cha)
• Photometry of some neglected bright cataclysmic variables and candidates
• Optical observations and cyclops post-shock region modelling of the polar V348 Pav
• Stream-field interactions in the magnetic accretor AO Piscium
• HS0551+7241: A New Possible Magnetic Cataclysmic Variable in the Hamburg/CfA Bright Quasar Survey
• UU Aqr - No superhumps but variations on the time scale of days
• On the Impact of the Numerical Method on Magnetic Reconnection and Particle Acceleration -- I. The MHD case
• Photometric variability of the nova-like object V380 Oph in 1976-2016

Cited by in corpus (6)

• TESS light curves of cataclysmic variables -- II: Superhumps in old novae and novalike variables
• BO Ceti: Dwarf Nova Showing Both IW And and SU UMa-Type Features
• Spectroscopic Observations of V455 Andromedae Superoutburst in 2007: the Most Exotic Spectral Features in Dwarf Nova Outbursts
• Confirmation of SRGt 062340.2-265751 as a nova-like cataclysmic variable with a possible magnetic nature
• Scientific Validation of the SPARC4 Pipeline: Multi-band Imaging, Polarimetry, and Photometric Time Series for Improved Characterization of Transiting Exoplanets
• LAMOST J2043+3413 -- a Fast Disk Precession SW Sextans Candidate in Period Gap