SDSS J085414.02+390537.3 -- a new asynchronous polar

A. I. Kolbin; M. V. Suslikov; V. Yu. Kochkina; N. V. Borisov; A. N. Burenkov; D. V. Oparin

paper

SDSS J085414.02+390537.3 -- a new asynchronous polar

arXiv:2308.04597

Abstract

The asynchrony of the polar SDSS~J085414.02+390537.3 was revealed using the data of ZTF photometric survey. The light curves show a beat period $P_{b e a t} = 24.6 \pm 0.1$ ~days. During this period the system changes its brightness by $\sim 3^{m}$ . The periodograms show power peaks at the white dwarf's rotation period $P_{s p in} = 113.197 \pm 0.001$ ~min and orbital period $P_{or b} = 113.560 \pm 0.001$ ~min with the corresponding polar asynchrony $1 - P_{or b} / P_{s p in} = 0.3%$ . The photometric behavior of the polar indicates a change of the main accreting pole during the beat period. Based on the Zeeman splitting of the H $β$ line, an estimate of the mean magnetic field strength of the white dwarf is found to be $B = 28.5 \pm 1.5$ ~MG. The magnetic field strength $B \approx 34$ ~MG near the magnetic pole was found by modeling cyclotron spectra. Doppler tomograms in the H $β$ line demonstrate the distribution of emission sources typical for polars.