MBCAA Observatory

WX Cet outburst

Observations: 10, 11, 12, 13 Dec 2004

Michel Bonnardeau
11 Dec 2004
Updated: 12, 13, 14 Dec 2004
Revised: 15 January 2005

Abstract

On Dec 10, 2004 I discovered the UG dwarf nova WX Cet as being unusually bright. Light curves follow.

Observations

Actually, this is a rediscovery: see the AAVSO-discussion group, P. Schmeer, 6 Dec 2004.

The observations were carried out with a 203 mm SC telescope fitted with a SBIG ST7E camera (KAF401E CCD) and a Clear filter. 521 images were obtained in 4observing sessions on 10, 11, 12, 13 December 2004. Each exposure is 1-minute long.

For the differential photometry, the comparison star is LONEOS WX Cet 1 with an assumed unfiltered magnitude of 10.1. The check star is LONEOS WX_CET with a measured average magnitude of 11.358 and a standard deviation of 0.013.

The light curves:

Red: WX Cet; Green: check star. The error bars are +/- the 1-sigma statistical uncertainties. The magnitudes of the check star are shifted by +1 magnitude.
At the end of the session, WX Cet was very low over the horizon (air mass >3).
The average magnitude of WX Cet is 12.080.

The average magnitude of WX Cet is 12.205.

The magnitudes of the check star are shifted by +1.2 magnitude.
The average magnitude of WX Cet is 12.345.

The peak in the check star at 353.221 is due to a cosmic. The magnitudes are shifted by +1.3 magnitude.
The average magnitude of WX Cet is 12.513.

Analysis

The light curves show 10 "humps" at:

HJD - 2453000 uncertainty

350.372 0.002

350.431 0.002

351.263 0.001

351.326 0.0025

352.221 0.003

352.275 0.001

352.336 0.003

353.230 0.002

353.285 0.002

353.350 0.004

There is also a systematic uncertainty of 80 seconds to be added.

Assuming they are periodic, a best fit gives the period P and the origin t0:

P = 1.522 h
t0 = 2,453,350.373 HJD

and the O - C diagram: