The Discovery of a Persistent Quasi-Periodic Oscillation in the Intermediate Polar TX Col

TL;DR

This paper reports the discovery of a persistent ~5900 s quasi-periodic oscillation in TX Col, likely caused by the interaction between orbiting blobs in the accretion disk and the white dwarf's spin, based on 12 years of photometry.

Contribution

It introduces a new detection of a quasi-periodic oscillation in TX Col and proposes a novel model involving blob accretion and beat frequencies to explain it.

Findings

Detection of a ~5900 s quasi-periodic variation in TX Col

Proposed model involving beat frequency between orbital blobs and spin

Long-term photometry confirms persistence of the oscillation

Abstract

We report on the detection of an ~5900 s quasi-periodic variation in the extensive photometry of TX Col spanning 12 years. We discuss five different models to explain this period. We favour a mechanism where the quasi-periodic variation results from the beating of the Keplerian frequency of the `blobs' orbiting in the outer accretion disc with the spin frequency, and from modulated accretion of these `blobs' taking place in a shocked region near the disc/magnetosphere boundary.