(cba:news) V455 And and RX0232-37

Joe Patterson jop at astro.columbia.edu
Fri Oct 5 14:43:17 EDT 2007

Dear CBAers,

Well, the V455 And = HS2331 coverage continues good, though down from 
the frenetic pace of mid-September.  The main periodic signals are 
basically standard fare for some of the WZ Sge stars: a strong signal
at Porb - with an origin still unknown - followed by a superhump.
No certifiable echo outbursts yet, but they could still come.

An important and unexpected wrinkle is the fast signal at 68 s.  It's 
actually present throughout the outburst, and CBA data will specify 
what happens to the phase/period as the outburst fades.  Keep that fast 
photometry coming (and by the way, if you possibly can, specify time to 
6 decimal places (JD xxx.yyyyyy).  Probably that sixth place is 
unimportant... but in playing with the data, I've noticed that roundoff 
errors can be detectable.  For most of you, though, I imagine that the 
star's faintness, your readout time, and timekeeping accuracy will keep 
you away from studying this signal.  That's fine - the most important 
lessons we're likely to learn from the eruption reside in the behavior 
of the slower periodic signals, and the eclipses.  Cycle times around 
40-60 s are likely to be just fine.

I've been delinquent in not writing about RX0232-37.  This is a newly 
erupted dwarf nova, and Greg Bolt has found strong superhumps... so it's 
one of our friends.  I believe it's still around V=11.7 or so, and may 
become quite an important star since it has to be quite nearby.  This is
really well placed for southern observers, and I fervently hope you'll 
spring to action pronto!  (Even though I didn't.)  The J2000 coords
                 02h 32m 38.13s
                -37d 17m 54.7s

Find yourself a nice comp star and fire away!  Having reached 10th mag 
or so, this star has great, great potential.


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