[vsnet-alert 13262] ER UMa: negative-postive superhumps appear

[Ohshima]

ER UMa: negative-postive superhumps appear

 We have received further obsevrations from Akazawa-san, Enrique de Miguel,
and Crimean Astrophy. Obs. (observers: Denis Samsonov). And we also took
observations of this object.
 This object showed the combination of negative and superhumps on Apr 27.8. 
 Negative superhumps seem to appear and disappear every other days in the
early stage of this superoutburst. This might be related to the beat 
cycle of neghative superhumps and positive superhumps (nearly 1 day).
Meanwhile the last observations immlies that negative superhumps have been 
continuously seen for two days. It is unknown whether this shows the change
of superhumps phase or simply the positive superhumps appearred in the blank
of observations. 
 Further osbervations are encouraged!