(cba:news) VX For in outburst - at last!

Joe Patterson jop at astro.columbia.edu
Mon Sep 14 12:51:40 EDT 2009

Dear CBAers,

Wow, I've lived to see the day!

This star zoomed to 12.6 from about 20.5 in 1990, and stayed bright for 
many weeks (declining at ~0.1 mag/day).  The spectra made it pretty 
clear it was an erupting dwarf nova, and even in 1990 it seemed very, 
very likely that the star would flash superhumps.  But I studied it for 
7 straight nights at Cerro Tololo, and found only small and apparently 
aperiodic wiggles in the light curve.  Basically a very high-quality 
nothing.  Then my run ended... and I've always wondered what this star is.

Now it's 2009, and we know a lot more about the WZ Sge syndrome among 
dwarf novae.  The most extreme of these stars generally take quite a 
long time to sprout actual superhumps; WZ Sge itself takes 10 days. So 
that's a pretty good conjecture - that it's quite extreme even among the 
WZ Sge class... and that had I taken over that 0.9 m telescope and 
refused to leave, I would eventually have seen those telltale superhumps.

We don't yet know much about this eruption, but if it's a super (odds 
are decent), then this is the glamor object of the year for dwarf novae.
We also don't yet know when it erupted.  This one's only for 
southerners... but I'll definitely be thrilled to see any data you can 
get on it!

The basic info is all in the Downes catalog.

And the good early-night southern target continues to be V4743 Sgr.  So 
far, our late-season coverage of this star is just a few short runs from 
Bob Rea - it would be nice to see that firmed up.  A good star to 
sacrifice, in order to get substantial time on these two targets, is BW 
Scl.  We can definitely suspend the latter campaign for a while - maybe 
for the season.


-------- Original Message --------
Subject: [vsnet-alert 11471] VX For outburst
Date: Tue, 15 Sep 2009 02:13:48 +1000
From: Rod Stubbings <stubbo at sympac.com.au>
To: <vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp>
CC: cvnet-outburst at yahoogroups.com

The probable dwarf nova VX For appears to be in outburst.  I have never 
this star in outburst before and the only information on it is from IAUC
5127, 1990 on the discovery.

FORVX          090914.636   130  Stu.RASNZ

Rod Stubbings.

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