Rapid Oscillations in Cataclysmic Variables. XVI. DW Cancri

Abstract

We report photometry and spectroscopy of the novalike variable DW Cancri. The spectra show the usual broad H and He emission lines, with an excitation and continuum slope characteristic of a moderately high accretion rate. A radial-velocity search yields strong detections at two periods, 86.1015(3) min and 38.58377(6) min. We interpret these as respectively the orbital period P_orb of the binary, and the spin period P_spin of a magnetic white dwarf. The light curve also shows the spin period, plus an additional strong signal at 69.9133(10) min, which coincides with the difference frequency 1/P_spin-1/P_orb. These periods are stable over the 1 year baseline of measurement. This triply-periodic structure mimics the behavior of several well-credentialed members of the "DQ Herculis" (intermediate polar) class of cataclysmic variables. DQ Her membership is also suggested by the mysteriously strong sideband signal (at nu_spin-nu_orb), attesting to a strong pulsed flux at X-ray/EUV/UV wavelengths. DW Cnc is a new member of this class, and would be an excellent target for extended observation at these wavelengths.

PDF, 28 pages, 6 tables, 9 figures; accepted, in press, to appear June 2004, PASP; more info at http://cba.phys.columbia.edu/

References in corpus (3)

• A precise HST parallax of the cataclysmic variable EX Hydrae, its system parameters, and accretion rate
• DW Cancri: a magnetic VY Scl star with an orbital period of 86 minutes
• Kilo-Second Quasi-Periodic Oscillations in the Cataclysmic Variable DW Cancri

Cited by in corpus (18)

• Magnetic White Dwarfs
• SDSS unveils a population of intrinsically faint cataclysmic variables at the minimum orbital period
• The Accretion Flows and Evolution of Magnetic Cataclysmic Variables
• Cataclysmic variables from a ROSAT/2MASS selection I: Four new intermediate polars
• Parallax and Distance Estimates for Twelve Cataclysmic Variable Stars
• Dwarf novae in the Hamburg Quasar Survey: Rarer than expected
• SDSS J233325.92+152222.1 and the evolution of intermediate polars
• Optical and X-ray Studies of Ten X-ray Selected Cataclysmic Binaries
• IPHAS J062746.41+014811.3: a deeply eclipsing intermediate polar
• Exploratory Spectroscopy of Magnetic Cataclysmic Variables Candidates and Other Variable Objects
• DW Cancri in x-rays
• The Unusual Cataclysmic Binary Star RBS 0490 and the Space Density of Cataclysmics
• New observations of DW Cnc: where is the 38 min signal?
• The return of the spin period in DW Cnc and evidence of new high state outbursts
• DW Cnc: a micronova with a negative superhump and a flickering spin
• Very fast photometric and X-ray observations of the intermediate polar V2069 Cygni (RX J2123.7+4217)
• New Photometry and Spectroscopy of DW Cnc
• Investigating the low-flux states in six Intermediate Polars