(cba:news) HV Vir jumps into superoutburst, probably

[Joe Patterson]

Dear CBAers,

Patrick Schmeer just found another very lazy dwarf nova in eruption,
around mag 12.5 or so.  It's HV Vir, last glimpsed by small telescopes in
1992.  It's likely that the present outburst is a super, in which case
we'll definitely want to train some telescope power on it.  The only
drawback is the RA - Virgo isn't ideal this time of year.  On the other
hand, it erupts only once every decade or so, so we can't be too
finicky... and with good longitude distribution for equatorial stars, we
can hope to track it fairly well even though no one observer can get
really long runs.

It's a classic CBA target, calling for long time series in (predominantly)
unfiltered light... patch some different longitudes together, and we'll
get very good coverage.  Definitely the prime after-midnight target out
there.  Likely to display a rich superhump structure like WZ Sge - which
flashed 17 noncommensurate periods!

For southerners, TX Col is priority one now; Fred and Jennie kicked off
the season with a great run on January 2.  Bob, it's time to bring the BW
Scl campaign to a close.  The other object I wanted to put forward now
is T Pyx: we've been timing the orbital hump now for 6 years, and are
on the verge of being able to nail down the orbital ephemeris over a
15-year baseline.  The results suggest, but do not conclusively prove,
that the period is increasing on a timescale of ~5x10**5 years.  This
would require a powerful mechanism for self-destruction in the
binary.  But first we need to know sure: is it really blowing itself
apart that fast?

For northerners I'd recommend FS Aur and/or BK Lyn as the early targets of
choice, followed by HV Vir.  It's presumably the last call for HV this
decade, and the data should be quite gorgeous... what's a little winter
chill compared to that?

   joe

all targets on "charts" page of website.