(cba:news) Call off the dogs

Joe Patterson jop at astro.columbia.edu
Sun Sep 24 11:15:51 EDT 2000

Dear CBAers,

Volleys of data on UU Aqr continue to pound the CBA website, and amid all 
the smoke and the tumult I faintly heard a cry of "enough!".  Assuming I
understand Aquarian talk.  Mostly the stars defeat us of course, but in
this one case I think we have enough data to learn everything about
the star that this type of observation will let us learn.  22 straight 
nights of two-longitude coverage (NZ and USA), with a few commando raids
from Europe as well.  Gotta give Old Man Weather some credit here too.

So let's officially recognize UU Aqr's surrender.  A well-credentialed
apsidal superhumper with a period excess of 7.0%, and lovely eclipses
which are going to tell us the shape of the accretion disk.

Since we're doing so well in Aquarius, let's shift to HL Aquarii (2000
coords 22 20 27.03 +02 00 53).  This star has V~13.6, so it can be done by
any aperture and in practically any moonlight.  I've taken a few peeks at
it.  It has some kind of a photometric wiggle around 3.2 hours, but we've
never gotten enough data to find out if it's an orbital signal, a
superhump, or what.

The other equatorial star to do right now is V1432 Aql = RX1940.2-1025.
Unlike HL Aqr - which will never delight you as its light curve is pretty
flat - this star is one of the most active in the sky, with rapid
flickering, huge humps, and sharp, deep eclipses.  It's late in the
observing season, but with so much recent AU/NZ/USA teamwork, I think we
can still mount a good 3-4 week campaign.  Next year it will be one of our
main targets.  It's a so-called "asynchronous AM Her", in which the
magnetic white dwarf has strayed from synchronism and is, perhaps, trying
to re-lock.

Kiwis might want to confer among themselves and each take one or the other
of these (HL or V1432).  Same for northerners.

V1432 chart at CBA website, HL Aqr in Downes and Shara (Feb 1993 PASP).

And for southern stars, there's still VY Scl, for which Paul Warhurst
started the season.  Let's keep going on this too.

In the north, the extra stars are GD 552 = Cep 1 and Z And, as described      

Finally, I make my usual plea for occasional sniper fire at the DQ Her
stars, which we want to study over the long haul for rapid period changes.
Targets in question are V1223 Sgr, FO Aqr, AO Psc, V709 Cas, V405 Aur,
and BG CMi.  Go, go, yay team.


Four word summary: HL Aqr, V1432 Aql

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