Time-resolved photometry and spectroscopy of the new deeply-eclipsing SW Sextantis star HS 0728+6738

Abstract

We present time-resolved optical spectroscopy and photometry, and far-ultraviolet spectroscopy of HS 0728+6738, a cataclysmic variable discovered in the Hamburg Quasar Survey. We show that the system is a new eclipsing member of the SW Sex class of CVs with an orbital period of 3.21 hours. We derive an orbital inclination of ~85 +- 4 degrees from the average eclipse profile, making HS 0728+6738 the highest inclination SW Sex star known. The optical and far-ultraviolet emission lines are not or only weakly occulted during the eclipse, indicating the presence of line-emission sites either far outside the Roche lobe of the primary or, more likely, above the orbital plane of the binary. The photometric light curves exhibit fast variability with a period of \~7 min, which might be related to the spin of the white dwarf.

arXiv comment9 pages, 11 figures, accepted for publication in A&A

References in corpus (14)

• Anomalous ultraviolet line flux ratios in the cataclysmic variables 1RXSJ232953.9+062814, CE315, BZ UMa and EY Cyg observed with HST/STIS
• 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
• HS2237+8154: On the onset of mass transfer or entering the period gap?
• VY Sculptoris stars as magnetic CVs
• Ultraviolet Emission Line Ratios of Cataclysmic Variables
• Optical studies of the X-ray transient XTE J2123-058 - II. Phase-resolved spectroscopy
• Superhumps in V348 Pup
• A spectrophotometric study of RW Trianguli
• 1RXSJ062518.2+733433: A new intermediate polar
• V348 Puppis: a new SW Sex star in the period gap
• Spectropolarimetry of the nova-like variable V1315 Aql
• The Intriguing New Cataclysmic Variable KUV03580+0614

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• Dwarf novae in the Hamburg Quasar Survey: Rarer than expected
• HS0139+0559, HS0229+8016, HS0506+7725 and HS0642+5049: Four new long-period cataclysmic variables
• IPHAS J062746.41+014811.3: a deeply eclipsing intermediate polar
• An evolved donor star in the long-period cataclysmic variable HS 0218+3229
• HS 0943+1404, a true intermediate polar
• Detection of the white dwarf and the secondary star in the new SU UMa dwarf nova HS 2219+1824
• OPTICAM: A triple-camera optical system designed to explore the fastest timescales in Astronomy
• On the M_V -- Inclination Relationship for Nova-like Variables
• The Eclipsing Cataclysmic Variable Lanning 386: Dwarf Nova, SW Sextantis Star, or Both?
• A spectroscopic analysis of the eclipsing nova-like EC21178-5417 -- discovery of spiral density structures