PTF1J2224+17: A short-period, high-field polar

Abstract

We present time-resolved photometry of the cataclysmic variable PTF1J2224+17 obtained during four nights in October 2018 and January 2019 from Inastars observatory. The object is variable on a period of 103.82 min. Archival Catalina Real-Time Transient Survey (CRTS), Palomar Transient Factory, and Zwicky Transient Facility-data show frequent changes between high and low states. Based on its photometric properties and the cyclotron humps in the identification spectrum the object is certainly classified as an AM Herculis star (or polar) with a likely magnetic field strength of B∼65 MG. Its accretion duty cycle was estimated from 9 years of photometric monitoring to be about 35%.