Fading of V803 Cen

2003 June superoutburst

The AM CVn-type helium cataclysmic variable (CR Boo -like) object V803 Cen is fading as indicated by the following alert message.

(vsnet-alert 508)

Dr Frank Bateson, VSS RASNZ, reports the fading of the R CrB star V803 Cen:

Date         UT       Mag      Observer
Aug   05    11:04     13.4      Rod Stubbings,Drouin, Australia
      10     10:37    <14.2     Rod Stubbings
      14     10:24    <15.0     Peter Nelson,Ellinbank, Australia

Peter Nelson
e-mail: pnelson@dcscomp.com.au

Comment by T. Kato

Dear Peter Nelson and southern friends,

V803 Cen is now considered to be a double-degenerate helium cataclysmic varible of AM CVn-type (see O'Donoghue et al. 1987, MNRAS 227, 347 for an early report; various good review articles exist on AM CVn stars, e.g. Warner 1995, ApSS 225, 249). Since V803 Cen is known to show large amplitude variations as in CR Boo, close monitoring of this object may reveal its still poorly understood outburst (or fading) property. The northern counter- part, CR Boo, has been recently shown by Patterson et al. (cf. vsnet messages Nos 606, 607 and 645) to erupt every 0.8 day during its normally outbursting phase, and to exhibit superhumps during its long-lasting bright outbursts. Observers of V803 Cen are therefore requested to monitor this object every clear night (hopefully several times a night), rather than what is used to be done for monitoring R CrB stars.

Regards,
Taichi Kato