(cba:news) CSS J174033.5+414756 outburst!

[Joe Patterson]

Dear CBAers,

This quite strange star is again in outburst. While it is possibly a 
"short outburst" - without any definite model implies by this term! - 
it's far too interesting to pass up.  Let's jump on it right away!

My notes say that the preferred comparison stars (used last year) are:
JJ: 000-BKZ-140 (V=13.761)
EA: GSC 3096-1994 (V=13.441)

I even think that this is now the *top priority* target for northerners. 
  Much as I love V1494 Aql and all the great data you guys are getting, 
I think this one is more important and time-critical now.
The novae can wait a little bit.

But - just to stay reasonably loyal to classical novae - I wanted to 
endorse V4743 Sgr again (so far only Berto has observed it this year), 
and also V1974 Cyg (pretty faint, so you might want to wait for good 
conditions).

joe


-------- Original Message --------

From: Denis Denisenko <d.v.denisenko at gmail.com>
To: vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp
Content-Type: text/plain; charset=UTF-8
Subject: [vsnet-alert 17610] CSS J174033.5+414756 outburst

X-DSPAM-Signature: 53e4a177220533702315154

This very unusual large amplitude (~7m) short-period (65-min) dwarf
nova in Hercules is in outburst! Last negative observation was a week
ago.

CSS J174033.5+414756 (ASASSN-13ae)
   20140730.120  <142V   C. Chiselbrook (AAVSO)
   20140806.109   138V   C. Chiselbrook (AAVSO)
   20140806.993  13.98V  J.-L. Gonzalez Carballo (AAVSO)
   20140807.087   139V   C. Chiselbrook (AAVSO)
   20140807.157  13.77V  J. O'Neill (AAVSO)

Light curve of CSS 130418:174033+414756 from Catalina Sky Survey:
http://nesssi.cacr.caltech.edu/catalina/20130418/1304181400734166981p.html

Previous outbursts: 2013 Apr. 18 (discovery by CSS), 2007 May 15
(found post factum in CSS data). There was extensive observing
campaign in April-May 2013 following [vsnet-alert 15629]. The
photometric behavior (~50 days long superoutburst and evolution of
superhumps) plus presense of Hydrogen lines in spectra allowed to
classify the star as UGWZ dwarf nova. The period around 0.045d makes
it an extremely unusual object. Yet now we have an outburst just 15.5
months after the previous one!

Denis Denisenko



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