Orbital periods of cataclysmic variables identified by the SDSS. III. Time-series photometry obtained during the 2004/5 International Time Project on La Palma

TL;DR

This study provides detailed time-series photometry of 15 SDSS-identified cataclysmic variables, revealing their orbital periods, light curve features, and some unique behaviors, enhancing understanding of CV subtypes and period distribution.

Contribution

First comprehensive orbital period measurements for 11 SDSS CVs, including several with unique features like deep eclipses and non-radial pulsations, expanding knowledge of CV characteristics.

Findings

Most systems are below the 2-3h period gap.

Five systems are near the ~80min minimum period.

Identification of deeply eclipsing and highly modulated CVs.

Abstract

We present time resolved CCD photometry of 15 cataclysmic variables (CVs) identified by the Sloan Digital Sky Survey (SDSS). The data were obtained as part of the 2004/05 International Time Programme on La Palma. We discuss the morphology of the light curves and the CV subtypes and give accurate orbital periods for 11 systems. Nine systems are found below the 2-3h orbital period gap, of which five have periods within a few minutes of the ~80min minimum orbital period. One system each is found within and above the gap. This confirms the previously noted trend for a large fraction of short-period systems among the SDSS CVs. Objects of particular interest are SDSSJ0901+4809 and SDSSJ1250+6655 which are deeply eclipsing. SDSSJ0854+3905 is a polar with an extremely modulated light curve, which is likely due to a mixture of cyclotron beaming and eclipses of the accretion region by the white dwarf. One out of five systems with white-dwarf dominated optical spectra exhibits non-radial pulsations.