(cba:news) The 1997 Haul...
jop at astro.columbia.edu
Mon Dec 22 16:48:02 EST 1997
Dear CBAers, Dec. 22, 1997
What a great year it's been!
It's hard to even count all the nice things that came our way this
year. We found two really bright, powerful superhumpers in TT Ari and
V592 Cas. I believe that our study of these stars will provide the
world's basic information on the long-term evolution of apsidal
superhumps. And they are bright enough for the humblest of our
telescopes, the 8-inchers with crummy skies.
Three unexpected, essentially new dwarf novae popped up in the spring
and received intense coverage: V844 Her, VW CrB, and USNO pile-o-
digits. We found accurate periods for each, and they were all short:
79, 80, and 81 minutes.
We found another dwarf nova with an ultra-short recurrence period: V803
Cen, outbursting every 22 hours. Poster star for global photometry!
We found the orbital period of AM CVn, at 1028.7 seconds. Searched for
intensively since the early 1960s, and now found.
We amassed a huge study of EG Cancri, king of the echo outbursts.
We greatly extended our study of the SW Sex stars, which seem so
remarkably enamored of negative superhumps.
And much else besides. On the empire side of the ledger, we enrolled
new observing stations in New Zealand, Russia, and South Africa. The
New Zealand connection has been superb, with three productive observers
(Stan Walker, Paul Warhurst, and Marc Bos). CBA-Illinois, under
Jerry Gunn, also came on board and is proving to be a strong node in
And Jonathan has got a good web site up and running. (You make him
happy when you visit it.)
So there's all that to be thankful for. I think it was a year of good
health for CBAers too, though my morning mail has less information
about that than about the latest celestial wiggles.
And what for the new year?
The strategy on V592 Cas and TT Ari is similar. For both stars, we
have obtained intervals of ~15 d of *dense* coverage, which permits
sensitive searches for periodic signals. And the results are fairly
simple: very stable apsidal superhumps at 0.1223 and 0.1492 d
respectively (with a few harmonics as usual). That project is done.
The second project is to study slow period changes by tracking the
signals as late as possible in the observing season (Jan 20 maybe?),
then resuming as early as possible next year. In effect, that means
the stars remain ideal targets for the smallest and most northerly
telescopes. But the bigger telescopes and those below +40 degrees
should probably sign off.
The observing season has also ended for V503 Cyg, FO Aqr, and
PX And. I still hope for late-season timings of AO Psc, though.
A really good star for coverage now is "Tau 2" (the name in
Downes-Webbink-Shara, where there's a chart). It has V~15.5 and is
accessible to everyone at J2000 4h 00m 37.3s, +6d 22m 46s (2 arcmin SW
from a bright star). Still unstudied, but a promising applicant for
one of our clubs (SW Sex or DQ Her). If you can use the bright star as
a comparison without saturation, do so; otherwise trust your judgment
and tell me which comparison you used.
Another good one is "Tau 1" = V1062 Tau. Candidate periods at 10
and 1 hr. This one's a little harder at 16. Chart in the original
CN Ori is also good any time (quiescent or erupting), and RZ LMi
is good if in eruption (which it does quite a lot).
For the Australites, AH Men = Men 1 and RR Pic are the targets of
choice these days. Bright and southerly and humpy.
Finally here are a couple of truly weird ones, emission-line stars
that live in small gamma-ray (100 MeV) error boxes. We dunno what they
are, but two types of measurement would be nice: BVRI magnitudes (for
those with filters) and nightly delta-mags with respect to a fixed
comparison star. A time series might be good too, who knows? Here are
their J2000 positions: 22h 26m 38.7s, +61d 13m 32s; and 06h 35m 18.3s,
+05d 33m 06s. Each has V near 12.2 (I think). The second one has a
13th mag star, a promising comparison, about 30" N of it. But the
first is on the edge of a dark cloud, and you're on your own! Happy
hunting, lemme know what you find!
Now I get to go off for my own winter holiday. And I have a new
modem now, so please write!
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