The nature of the cataclysmic variable PT Per

M G Watson,A Bruce,C Macleod,A D Schwope,J P Osborne

doi:10.1093/mnras/stw1292

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.

Highlights

IntroductionThe XMM-Newton serendipitious survey catalogues (2XMM; 3XMM, Watson et al 2009; Rosen et al 2016) and their associated data (spectra and time series for individual X-ray sources) provide a rich resource for exploring both Galactic and extragalactic source populations down to relatively faint X-ray fluxes (∼ 10−14 erg cm−2 s−1)
The XMM-Newton serendipitious survey catalogues (2XMM; 3XMM, Watson et al 2009; Rosen et al 2016) and their associated data provide a rich resource for exploring both Galactic and extragalactic source populations down to relatively faint X-ray fluxes (∼ 10−14 erg cm−2 s−1)
We have presented a study of PT Per based on archival XMM-Newton X-ray data and new optical spectroscopy from the WHT with Intermediate dispersion Spectrograph and Imaging System (ISIS)

Summary

Introduction

The XMM-Newton serendipitious survey catalogues (2XMM; 3XMM, Watson et al 2009; Rosen et al 2016) and their associated data (spectra and time series for individual X-ray sources) provide a rich resource for exploring both Galactic and extragalactic source populations down to relatively faint X-ray fluxes (∼ 10−14 erg cm−2 s−1). The most recent catalogue (3XMM-DR5) covers around 2% of the sky and contains spectra and time series for 24% of the ≈ 400000 sources (Rosen et al, 2015). In this paper we present the discovery of periodic eclipse-like features in the X-ray light curve of the cataclysmic variable (CV) PT Per which was in the field of view of an XMM-Newton observation made in 2011 and discuss the nature of this system. PT Per is a relatively obscure and little studied cataclysmic variable (CV). It is listed in the Downes et al (2001) catalogue as a U Gem (dwarf nova) system with magnitude in the range ∼15 - 18.5m. The possibility exists that the wrong star was observed as noted by Downes et al (2001)

Results

Discussion

Conclusion