Optical Studies of Seven Bright Southern Cataclysmic Variable Stars

TL;DR

This study presents spectroscopic observations of seven bright southern cataclysmic variable stars, determining their orbital periods and analyzing their spectral and photometric behaviors using multiple data sources.

Contribution

The paper provides new orbital period measurements for five cataclysmic variables and combines spectroscopic and TESS data to analyze their accretion disk precession and variability.

Findings

Orbital periods determined for five stars.

TESS data confirms and refines orbital period for BMAM-V547.

Detected a photometric period near 3.93 days indicating disk precession.

Abstract

We report spectroscopic observations of seven bright southern cataclysmic variable stars, collected on a single two-week observing run using the 1.9-m Radcliffe telescope at the South African Astronomical Observatory. We used radial velocity time series, in some cases in combination with other data, to determine or clarify orbital periods for five of them, namely ATO J061.1478-31.0634, BMAM-V547, MGAB-V202, NSV 4202, and V1147 Cen. For BMAM-V547, we use data from the Transiting Exoplanet Survey Satellite (TESS) to corroborate and sharpen the orbital period; the TESS data also show a photometric period near 3.93 d, likely indicating precession of the accretion disk. Also, we find a periodic modulation in the radial velocities of the SU UMa-type dwarf nova Var Ret2005, but are unable to specify a unique cycle count. Finally, we show a spectrum of ASASSN-V J061528.41-412007.3 that appears typical of a luminous novalike variable.