[vsnet-chat 4647] Re: [vsnet-campaign 1015] WZ Sge extremely rare outburst

[erik kuulkers <erikk@sron.nl>]

Dear Patrick,

> On Tue, 24 Jul 2001, Patrick Schmeer wrote:
> WZ SAGITTAE  (UGSU)
> 
> ...
> 
> The intervals between the four known outbursts were 32.58, 32.43,
> and 22.64 years, respectively. So the current outburst occurs
> 10 years earlier than expected. What does this imply? Outbursts
> of WZ Sge do not occur very regularly? A few superoutbursts were
> missed during the last century (pretty unlikely)? Or could the
> current outburst be the first ever recorded normal outburst
> (mean cycle length about 11 years???)? 
> 
> ...
> 

It is known for several SU UMa stars that superoutbursts occur rather 
regularly. But every now and then they change their cycle length
(see Vogt N., 1980, A&A 88, 66). Admittedly though, they do not change 
their cycle length by that much; it's generally <10% or so.
Let's see if this is a normal outburst or not....

Regards,

Erik Kuulkers

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