The nature of the cataclysmic variable PT Per

TL;DR

This study characterizes PT Per as a likely magnetic polar cataclysmic variable with an 82-minute period, low accretion state, and a very low-mass secondary, based on X-ray and optical data analysis.

Contribution

It provides the first detailed multi-wavelength analysis of PT Per, identifying it as a potential period-bounce binary and clarifying its accretion state and system parameters.

Findings

PT Per has an 82-minute recurrence period in X-ray minima.

The optical spectrum is dominated by the white dwarf, indicating a low accretion state.

PT Per is likely a magnetic polar with a very low-mass secondary.

Abstract

We present a study of the cataclysmic variable star PT Per based on archival XMM-Newton X-ray data and new optical spectroscopy from the WHT with ISIS. The X-ray data show deep minima which recur at a period of 82 minutes and a hard, unabsorbed X-ray spectrum. The optical spectra of PT Per show a relatively featureless blue continuum. From an analysis of the X-ray and optical data we conclude that PT Per is likely to be a magnetic cataclysmic variable of the polar class in which the minima correspond to those phase intervals when the accretion column rotates out of the field of view of the observer. We suggest that the optical spectrum, obtained around 4 years after the X-ray coverage, is dominated by the white dwarf in the system, implying that PT Per was in a low accretion state at the time of the observations. An analysis of the likely system parameters for PT Per suggests a distance of $\approx90$ pc and a very low-mass secondary, consistent with the idea that PT Per is a "period-bounce" binary.