# CRTS J035010.7+323230, a new eclipsing polar in the cataclysmic variable period gap

## TL;DR

This paper reports the discovery and detailed characterization of CRTS J0350+3232, a new eclipsing polar in the cataclysmic variable period gap, providing insights into accretion processes and stellar parameters.

## Contribution

It presents the first identification, spectroscopic confirmation, and parameter estimation of a new eclipsing polar within the period gap, using multi-year photometry and spectroscopy.

## Key findings

- Confirmed CRTS J0350+3232 as a polar through spectral features and modulation.
- Derived precise binary parameters including inclination and stellar masses.
- Identified stream accretion evidence from pre-eclipse dips.

## Abstract

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 multi-year 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 $\lambda$4686{\AA} emission line equivalent width ratios, structures, and variations are typical of polars and are modulated at the same period, 2.37-hrs (142.3-min), as the eclipse to within uncertainties. The spectral energy distribution and luminosity is found to be comparable to that of AM Herculis. Pre-eclipse dips in the light curve show evidence for stream accretion. We derive the following tentative binary and stellar parameters assuming a helium composition white dwarf and a companion mass of 0.2 M$_{\odot}$: inclination i = 74.68$^{o}$ ${\pm}$ 0.03$^{o}$, semi-major axis a = 0.942 ${\pm}$ 0.024 R$_{\odot}$, and masses and radii of the white dwarf and companion respectively: M$_{1}$ = 0.948 $^{+0.006}_{-0.012}$ M$_{\odot}$, R$_{1}$ = 0.00830 $^{+0.00012}_{-0.00006}$ R$_{\odot}$, R$_{2}$ = 0.249 ${\pm}$ 0.002 R$_{\odot}$. As a relatively bright (V $\sim$ 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.