1RXS J161935.7+524630: New Polar with the Varying Accretion Modes on two Magnetic Poles

TL;DR

This paper reports the discovery of a new polar cataclysmic variable with changing accretion modes on two magnetic poles, evidenced by variable light curves and spectral features, indicating a dynamic accretion process.

Contribution

The study identifies a new magnetic cataclysmic variable with variable accretion modes on its poles, based on multi-epoch photometric and spectroscopic observations, revealing changes in accretion geometry over time.

Findings

Discovered a new polar with a 100.5-minute period.

Observed a transition from single to double accretion poles.

Detected prominent Helium emission lines indicating magnetic accretion.

Abstract

We report the discovery of a new cataclysmic variable DDE 32 identified with the ROSAT X-ray source 1RXS J161935.7+524630 in Draco. The variability was originally found by D. Denisenko on the digitized Palomar plates centered at the position of X-ray source. The photometric observations by F. Martinelli at Lajatico Astronomical Center in June 2015 have shown the large amplitude (nearly 2 magnitudes) variability with a period about 100.5 minutes. Using the publicly available Catalina Sky Survey data from 2005 to 2013 we have improved the value of period to 0.0697944 days. Comparison of the archival CRTS data with more recent observations from Lajatico shows the dramatic changes in the light curve shape. Instead of a single peak present in Catalina data before 2014, there were two peaks of nearly the same height during 2015. SDSS spectrum taken in June 2009 shows prominent Helium emission lines between the bright Balmer series. He II 4686 AA line has more than 30% effective width compared to H_beta line. All those features allow us to interpret 1RXS J161935.7+524630 as a magnetic cataclysmic variable (polar) with the accretion mode changing from one pole before 2014 to two poles in 2015.