(cba:news) Call off the dogs

Joe Patterson jop at astro.columbia.edu
Wed Oct 31 10:42:46 EST 2001

Dear CBAers,

Well, as you saw from Tonny's message, mister SDSS1730 slunk back to
quiescence, and WZ Sge is getting harder to observe, due to its own fading
and the hostility of the western horizon.  So it's time, finally, to call
off the dogs for both stars.  In a month's time we'll have another shot at
WZ with a big telescope, and we'll see if we can track the eclipse
waveform at that time... but after observing it for 94 out of 95 nights,
we should have learned the pattern by now!  (And we did.)

Whew, what a run, I hope we can rest for 25 more years.  Ha.

Meanwhile, there are other fish in the ocean.  Dave Skillman and Jerry
Foote are mounting a big campaign on TT Ari, which is pulsing away with a
big apsidal superhump.  This is an ideal target this time of year,
especially for small scopes since at V=10.8 there are lots of photons
available.  I hope that we can get some coverage from AU-NZ too... I know
you're not thrilled with the dec, but we still have no northern coverage
from CA to the Crimea, so we certainly do crave contributions from
Australasia and Oceania!

In principle,  TT Ari should be the star that will teach us all the
intricate details of apsidal superhumps, since it is so bright and roughly
equatorial.  So far, it appears to just flash a very powerful but
structureless superhump... but from past experience it seems a good bet
that the lack of structure merely reflects a lack of diligence in the
campaign.  November 2001 is the month to find out.

We have also received data on V592 Cas, mainly from Ed Beshore.  Kind of
a mystery, this one.  Two nights showed strong humps, and the other four
not.  This is sometimes means two closely spaced signals are beating
together, slowly travelling in and out of phase.  That interpretation
seems not to work for the present data... I just can't figger it out based
on the present data.  So we should either get a lot more, or give up!
Since it's a bright star and has a great dec for the Europeans, I'm
inclined to say let's hang in there for a few more weeks - and I hope the
Euros can bail us out!

Finally among northern targets is FS Aur.  This will be a major December
target, but it's important to get an early start, as the *precise* value
of the period is the key datum (to allow phasing with previous years) and
that is best served with the longest possible baseline of observation.
Another happily northern and decently bright (14) target.  It's a great
season for northern CBAers!  As usual, the best strategy is to settle on
one of these stars and fire away relentlessly on it.

Now for the south.  Thanks to Chen's recent article in MNRAS, identifying
numerous results from the Edinburgh-Cape survey for blue stars, we now
have a lot of fresh meat for hungry southern photometrists.  Among the
seasonal targets, the ones that seemed really promising to me are

EC23128-3105  23 12 50.0   -31 05 09  V=16.6 (sorry) but P estimated as
                                      1.4 hr
EC23593-6724  23 59 21.7   -67 24 28  V=14.3 (oooo) and P~2.0 hr
EC05114-7955  05 11 25.1   -79 55 02  V=15.1 and P~3.1 hrs

Coords  are 1950.0 by the way.  I think Jonathan has charts for all on the
CBA website.  All these stars looks astrophysically pretty interesting to

The other southern target is BW Scl.  We had a wonderful harvest from
Chile 2 weeks ago, supplemented by data from Bob Rea.  There is one strong
and probably stable period in the system, but we do need a longer baseline
of data in 2001 to guarantee an accurate cycle count over the season.  So
we definitely need another 4-6 weeks of coverage.  I apologize for the
faintness, and the ugliness of the light curve (just not a helluva lot
that grabs your eyeball... but oh, does that fourier transform love it!).
If you don't mind ugly depressing light curves, observe this star! -
otherwise you'll be a lot happier with the above list of 3.

Have a great ol' time observing... the ducks are on the proverbial pond.


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