2019MNRAS.488.2881M

We report the discovery of a new eclipsing polar, CRTS J035010.7+323230 (hereafter CRTS J0350+3232). We identified this cataclysmic variable (CV) candidate as a possible polar from its multiyear Catalina Real-Time Transient Survey (CRTS) optical light curve. Photometric monitoring of 22 eclipses in 2015 and 2017 was performed with the 2.1-m Otto Struve Telescope at McDonald Observatory. We derive an unambiguous high-precision ephemeris. Strong evidence that CRTS J0350 + 3232 is a polar comes from optical spectroscopy obtained over a complete orbital cycle using the Apache Point Observatory 3.5-m telescope. High velocity Balmer and He II λ4686Å emission-line equivalent width ratios, structures, and variations are typical of polars and are modulated at the same period, 2.37 h (142.3 min), as the eclipse to within uncertainties. The spectral energy distribution and luminosity is found to be comparable to that of AM Herculis. Pre-eclipse dips in the light curve show evidence for stream accretion. We derive the following tentative binary and stellar parameters assuming a helium composition white dwarf and a companion mass of 0.2 M_☉: inclination i = 74.68° ± 0.03°, semimajor axis a = 0.942 ± 0.024 R_☉, and masses and radii of the white dwarf and companion, respectively: M₁ = 0.948 ^+0.006_–0.012 M_☉, R₁ = 0.00830 ^+0.00012_–0.00006 R_☉, and R₂ = 0.249 ± 0.002 R_☉. As a relatively bright (V ∼ 17-19 mag), eclipsing, period-gap polar, CRTS J0350 + 3232 will remain an important laboratory for the study of accretion and angular momentum evolution in polars.