(cba:news) June stars

Joe Patterson jop at astro.columbia.edu
Wed Jun 8 16:39:38 EDT 2005

Dear CBAers,

Oops, it has been much too long!  I've been hard at work on data analysis
and writing up results for publication... and especially with V803 Cen (of
which, more below).  But time for an update on campaigns!

I was very surprised to read in the last 2 days the news that Tom and
Tonny had found superhumps in NSV 4838 = UMa 8... not because it's
unlikely, but because it's so late in the season.  Bravo!  The only thing
we can hope for is to use our longitude spread to count cycles (basically
between Europe and the U.S... since we don't have any Asian observers),
and get the superhump period.  The runs will be too short to assemble long
time series, but should be OK for time-of-maximum-light measurement.
Since no one has ever managed to measure this before, it's well worth

The other prime northern (OK, equatorial) star these days is RX1730-05 =
"Oph" in the Downes catalogue.  This star, usually around V=15.5, has a
128 s period in its light curve, with substantial power also at 64 s.  The
orbital period is still not known.  It should be red meat to us - assuming
you keep accurate time!  Awfully well placed in the night sky these days,
too.  Very, very nice challenge to CBAers of all conceivable longitudes
and latitudes!

There are competitor stars in the north and south.  In the north, the main
competition is "Her" = RX1643+34.  We did very well on this star in the
spring of '02, and published the results.  There were some loose ends, and
in particular the star shows the strongest persistent ~20 min
quasi-periodic oscillations of any star in the sky.  We've had it on the
list for a while... but no groundswell of popularity has resulted.
Nevertheless, it's a very deserving target!

And in the south, it's still V803 Cen.  As you might have noticed, Berto
found the star breaking out a new supermax two days ago - and since then,
Jennie McCormick and Bill Allen have obtained data from the other side of
the Earth.  And Paul Warhurst tells me he has obtained three nights of
observation from Argentina.  So we're doing pretty good.  Still, June is a
tad late for Centaurus, and it'll take some hard work to splice together a
really good light curve.  These outbursts are brief, so it's high time to
get an intense few nights more of observation!


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