The high-field polar RX J1007.5-2017

TL;DR

This paper presents multi-year optical and X-ray observations of the high-field polar RX J1007.5-2017, revealing its orbital period, magnetic field strength, and variability in accretion states over two decades.

Contribution

It provides detailed measurements of the magnetic field, orbital period, and variability of RX J1007.5-2017, expanding understanding of high-field polars through extensive observational data.

Findings

Orbital period of 208.60 min determined from secondary star modulation.

Magnetic field strength of 94 MG derived from cyclotron lines.

Significant variability in optical and X-ray luminosity over years.

Abstract

We report optical and X-ray observations of the high-field polar RXJ1007.5-2017 performed between 1990 and 2012. It has an orbital period of 208.60 min determined from the ellipsoidal modulation of the secondary star in an extended low state. The spectral flux of the dM3- secondary star yields a distance of 790+-105 pc. At low accretion levels, \RX{} exhibits pronounced cyclotron emission lines. The second and third harmonic fall in the optical regime and yield a field strength in the accretion spot of 94 MG. The source is highly variable on a year-to-year basis and was encountered at visual magnitudes between V \sim 20 and V \sim 16. In the intermediate state of 1992 and 2000, the soft X-ray luminosity exceeds the sum of the luminosities of the cyclotron source, the hard X-ray source, and the accretion stream by an order of magnitude. An X-ray high state, corresponding to the brightest optical level, has apparently not been observed so far.