MBCAA Observatory

RW Sex: a steady cataclysmic

Observations: 26, 29 April 2005

Michel Bonnardeau
3 May 2005

Abstract

Time-series of this NL cataclysmic are presented.

Introduction

RW Sex is a cataclysmic variable star, that is a binary star with an interacting white dwarf. It is classified as a NL (according to the GCVS it is also a ZZ (pulsating white dwarf) and according to other catalogs it is a UX). The orbital period may be measured by spectroscopy and is 5.9h.

RW Sex is a CBA target for April 2005.

Observations

The observations were carried out with a 203mm SC telescope, a Clear filter and a SBIG ST7E camera (KAF401E CCD). Each exposure has a duration of 60 seconds. 117 images were obtained.

RW Sex is much brighter than the stars that may be used for comparison so the statistical uncertainties come mostly from the comparison star. I use then 5 comparison stars to reduce this effect. I stacked all the images of the 26 April session and adjusted their magnitudes so that they fit the Pogson law. These comparison stars are:

GSC 5490-00 501 487 429 486 489

Unfiltered mag 13.884 14.374 13.051 13.618 12.593

The check star is GSC5490-00487 (which is also used as one of the comparison star).
A sample image with the field of view is here.

The results are:

Red: the light curve of RW Sex. The error bars are +/- the 1-sigma statistical uncertainties. Green: the light curve of the check star.

Variation of the air mass during the session.

According to Stokes et al (2000) 490.435 is the 0-phase of the orbital period.