[vsnet-outburst 7703] BZ UMa: rapid fading stage

[uemuram at hiroshima-u.ac.jp]

BZ UMa: rapid fading stage

We found that BZ UMa have entered in a rapid fading phase from the last superoutburst. The object was already at V~14.5, about 1 mag brighter than its quiescent level. The duration of the superoutburst is 12 days, typical one for ordinary SU UMa-type dwarf novae.

http://kanatatmp.blogspot.com/search/label/BZ%20UMa

During the rapid fading stage of BZ UMa, superhumps became quite prominent. We performed V- and J-band observations on 25 Apr. with TRISPEC/KANATA. The light curves show ~0.4 mag and ~0.2 mag humps in the V- and J-bands, respectively. They have double-peaked profiles in an superhump period. Compared with those observed on 23 Apr., just before the rapid fading, their amplitudes were very large last night.

Using a simple model with 2-component black body emissions, the V- and J-bands data indicates a superhump source with T~7500K on a stable disk with T~5000K. It is interesting that the heating mechanism by the tidal dissipation by the secondary star was still effectively working while the disk itself has almost returned to the quiescent one.

Regards,
Makoto Uemura and Akira Arai
on behalf of the KANATA team