HW Bootis: an enigmatic cataclysmic variable star

TL;DR

This study presents a 13-year light curve analysis of HW Boo, revealing irregular outbursts and hump-like variations, and discusses its possible classification as a dwarf nova or Intermediate Polar.

Contribution

The paper provides the first long-term light curve data of HW Boo and analyzes its outburst behavior and variability patterns, offering insights into its nature.

Findings

12 outbursts observed over 13 years

Irregular hump-like structures during outbursts and quiescence

Uncertain classification between dwarf nova and Intermediate Polar

Abstract

We present the 13-year light curve of HW Boo between 2001 May and 2014 May. We identified 12 outbursts, which typically lasted 2 to 5 days, with an amplitude of 2.7 to 3.6 magnitudes. Time resolved photometry during two outbursts revealed small hump-like structures which increased in size as the outburst progressed, reaching a peak-to-peak amplitude of ~0.8 mag. They occurred on timescales of 15 min to an hour, but did not exhibit a stable period. Similar irregular hump-like variations of 0.1 to 0.8 magnitudes, at intervals of 7 to 30 minutes, were also detected during quiescence. We discuss whether HW Boo might be a dwarf nova of the SU UMa family or an Intermediate Polar, but require further observations to support classification.