[vsnet-alert 4537] Re: BC UMa bright outburst

[Patrick Schmeer <p.schmeer@mx.uni-saarland.de>]

On Sat, Apr 01, 2000 at 05:42:42PM +0900, Taichi Kato wrote:
> BC UMa bright outburst
> 
>     Following observations have been reported.  BC UMa is one of famous
> large-amplitude SU UMa-type dwarf novae with very long outburst intervals.
> The latest outburst (according to my record) of BC UMa was observed on
> 1994 April 28, which was detected by M. Iida (VSOLJ) at mv=12.5, who
 
I can remember one (or maybe two) normal outbursts that occurred after
that supermaximum. In AAVSO NEWS FLASH No. 600 a July 1995 outburst is
mentioned.

>     BC UMa is one of famous dwarf novae which show both bright and faint
> superoutbursts (other known examples include SW UMa and WX Cet).  The
> present outburst is almost certainly one of "bright superoutburst" after
> the six years of dormancy.  The present brightness level was only reached
> on a few occasions, including the 1990 September outburst (mv=10.9, Dyck,
> IAUC 5089, unfavaorably located) and the 1982 May outburst (mv=10.7 according
> to the VSOLJ record).  The present outburst thus provides the first-ever
> favorable opportunity to clarify the nature of a bright superoutburst.
 
The 1990 outburst was independently detected by me on Sept. 9.82 UT at  
mv= 11.5: (cf. IAUC 5089).
 
Let us hope that the current outburst is a supermaximum. Since this outburst
has been detected so early and since BC UMa is still high in the sky after  
dusk, it would be the most favourably observable BC UMa superoutburst ever.
 
Regards,
Patrick

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