From jop at astro.columbia.edu  Thu May 21 06:51:15 1998
From: jop at astro.columbia.edu (Joe Patterson)
Date: Thu, 21 May 1998 06:51:15 -0400 (EDT)
Subject: (cba:news) v2051 Oph Erupts!
Message-ID: <199805211051.GAA21004@tristram.phys.columbia.edu>


Dear CBAers,

For a few days now, V2051 Oph has been bright (V=12).  It has done this a few times
in the last 20 years, but never, as far as I know, for an extended period.
The present brightening seems long enough to be deemed a superoutburst.
Because the star is an eclipsing system, it is of highest importance to
follow it with time-series photometry - the shape of the eclipses trace out
the distribution of luminous regions in the binary.  In my opinion, this
is the most important alert we have had in the (admittedly short) history
of the CBA.

The star is now transiting near midnight (nice), and the Moon is outa the
way.  The field is incredibly crowded, but, well, ya can't have everything.
For australites, this is your moment!  As long as it stays bright, it's a
superb target.  And even after it fades, give it your best shot.  The
historical data on other eclipsing SU UMas (that's a reasonable guess for
this guy, though not known) suggests that the eclipses get very deep and
steep-sided, suggestive of a hot white dwarf.

For borealites, this star is tough but not impossible, at -25 degrees.
Short of cutting down your favorite tree, give it your best shot!  (Less
than favorite trees, forget about.)

Brian Warner and Liza van Zyl are carrying out a multi-longitude campaign
in the south right now on GW Lib.  They might well be the prime
perpetrators of this (V2051 Oph) campaign, though the positions of the
stars are mostly in conflict.  Anyway, let's get what we can, these
opportunities are rare.  I observed V2051 Oph just once, exactly 20 years
ago.  What a fascinating light curve it had then... but I never really 
thought I would ever see it in superoutburst!

joe