[vsnet-alert 12759] ER UMa: normal outburst? following the superoutburst

[Taichi Kato]

ER UMa: normal outburst? following the superoutburst

   Akazawa-san (Okayama U. of Sci. team) and Enrique de Migeul have
reported most recent observations.  The object reached a short minimum
on Jan. 30, but soon started rising!
During the rising branch (recorded by Akazawa-san), negative superhumps
apparently disappeared transiently -- very suggestive that present
negative superhumps are a result or a cause of the superoutburst.
After then, de Miguel's observation again caught a growing signal
of some sort of superhumps (period not yet well established) during
the brightness peak of the subsequent normal? outburst.
O-C analysis of de Miguel's observations suggests that these humps
are not on a smooth extension of negative superhumps seen until early
Jan. 30.

de Miguel's description:

              There were hints in yesterday's data that the system
              was slowly getting brighter. Today the system has
              brightened (on average) by 1.44 mags. This appeas to be
              a normal outburst. Surprisingly, it keeps exhibiting
              modulations with varying amplitude. When these data are
              analyzed with ANOVA, the modulation has a periodicity
              of 0.058(3). Although it's (significantly) smaller
              than the negative Psh found so far, data are insufficient
              and the statisticial uncertainty is large. We'll see
              how this value changes when the data are combined 
              with data from other observers. The mean periodicity
              since coverage of this superoutburst started has not
              changed compared to the value found yesterda, 
              0.06227(5)d.