AB Nor: A new member of SU UMa-type dwarf novae

April outburst

The dwarf nova AB Nor experienced a rare outburst (14.4mag) as reported by R. Stubbings and A. Pearce on April 1. According to A. Pearce, the last outburst of AB Nor occurred in 1999 May (mv=14.7, positively recorded on three nights) (vsnet-alert 4568). After rapid declining to <15.2mag on April 5, R. Stubbings reported a remarkable rebrightening (14.0mag) on April 6. (vsnet-alert 4574, vsnet-alert 4578, vsnet-alert 4594).

Superhump detection

On April 8, W. S. G. Walker performed a run of 2.8 hours and measured one definite superhump with an amplitude of 0.4 magnitudes. Maximum was at Apr 08.55 and the period looked about 2 hours, perhaps as much as 2.2 hours. He also commented that it is very uncertain in the absence of a second peak (vsnet-alert 4589).

(Light curve of AB Nor on April 8 during the first confirmed superoutburst presented by W. S. G. Walker; vsnet-alert 4590)

From time-series observations on April 8 and 9, he estimate a superhump period to be around 0.078 to 0.079 d. The amplitude appeared smaller at ~0.3 magnitudes but the humps still have a sharp rise with some structure on the decline. (vsnet-alert 4597).

General Information for This Object