American Association of Variable Star Observers (AAVSO)
Thu, 08/25/2016 - 20:44

I note that the CV star CH UMA is currently undergoing a maximum. As I have several times in the past, I would call attention to this star's long-term lightcurve once again. Anyone who doesn't think that dwarf novae can drastically alter their outburst cycle, do really odd things, or even shut down activity all together for long durations, need only look at this star on a LCG 10,000 day plot. Whereas CH UMA had an outburst cycle of close to 11 months for years on end, it suddenly became dormant following an outburst in 2011 and in spite of very good coverage did not show any activity again until four years later! 

Now we've apparently seen two consecutive maxima, this time separated by an interval of ~14 months. Does this signal that the star is perhaps attempting to return to its old ways, or is something new and strange in store for us in coming years?

CH UMA is only one of many examples among the CVs that cries out for more folks to initiate, or keep up, nightly observations of them and why visual observations are just as important these days as ever.

J.Bortle   (BRJ)