(cba:news) GW Lib, SDSS1339+48, V4743 Sgr, and OT2138+26
jop at astro.columbia.edu
Sat May 22 00:58:40 EDT 2010
Time for some spring cleaning. Unless it goes steadily faint again, we
can leave CR Boo for the season. The campaign on OT2138+26 is going
well (good coverage from Bill Stein, Tom, Bill Goff, and Enrique)), but
the unfavorable placement of Pegasus in May creates problems. We
*really* could use some coverage from other longitudes - while hanging
onto our existing ones!
Helena (Uthas) is still at Kitt Peak, along with several Columbia
students, and is carrying out a campaign on a CV with a pulsating white
dwarf: SDSS1339+48 ("UMa" in Downes catalog). I would *love* to get
some CBA coverage on this star. It has a very long period
("superorbital"), which probably will require multi-longitude
observation to break the alias. In addition, the pulsations are
probably stable enough to reveal fine-structure effects (beating of
closely spaced signals, etc.) if we could get such data. I think that
at least some CBAers can get good data on this 17.5 mag star - the light
curve will be no beauty, but the power spectrum should show the
pulsations. We especially want European coverage, of course! Let's see
if Arto or Enrique rise to the challenge.
I admit the waxing Moon is no friend to this enterprise. But periodic
signals have a way of shining through... and anyway, our interest in
this star will go on at least a few weeks.
In the same vein, we're also campaigning on GW Lib, brighter at 16.5.
Clobbered by the Moon on certain nights because of its zodiacal
location, but happily southern and brighter. An excellent target for
southern telescopes, for two reasons: the pulsations, and the mysterious
"2.1 hour" signal of unknown origin. Our previous campaign showed that
it's actually a 4.2 hour signal (with most power at the first
harmonic)... now we want to go on it a while to test for stability.
These mysterious superorbital periods are still a total mystery in CVs
(about 10 of them).
Finally there's V4743 Sgr. We need one more season on this, or possibly
just one more month, to complete our study over an 8-year baseline.
It's back - I hope some southerners can help us wrap this one up.
If you'd like to receive any of our data on these various targets,
please ask! We don't yet have any automatic system for this, but are
developing one. In the meantime, try the old-fashioned way!
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