(cba:news) Stars for Feb/Mar

Joe Patterson jop at astro.columbia.edu
Sun Feb 23 12:26:44 EST 2003

Dear CBAers,

Data flow has slowed recently... has Tom Ridge got you all duct-taping
your observatories?

KQ Mon sort of fizzled.  We have a 12-day time series, with decent
coverage from many longitudes.  There's a pretty decent period around 9
hours.  Unfortunately, we can't do as much with this as usual.  First,
there's no spectroscopic period to compare with.  Second, the length of P
gives us problems with differential extinction; only long time series can
reveal long periods, and long time series require a wide range of
airmasses - so our (usually) unfiltered approach is perilous (since blue
stars are significantly more extincted at large airmass).  And third,
you've seen Arne's notes that this is a confused region with two crowding
stars, difficult or impossible to separate.  I believe we'll get this
period out of the data eventually (the signal popped up after analyzing
just the first 4 days, and I have 8 more to go)... but it's definitely a
toughie!  Not as much fun to work on.  So let's retire KQ Mon.

Ye australites, what of NSV 10934?  The outburst is over, but I was hoping
we might able to get Po from photometry at quiescence.  That would provide
a nice bookend for a matched (Po,Psh) pair - one of our major goals.

It's a perfect time of year, and month, for PG1000+667 (UMa7 in CV Cat),
recently found to be a VY Scl star with a 3.4 hr orbital period.  This
makes it an excellent superhump candidate, and with that declination and
the snow on the ground, you can get data all night long.  Should yield
quickly to a CBA onslaught!

Rod Stubbings just reported a bright outburst of CAL 86, a Milky Way CV
along the line-of-sight to the LMC.  At 13.2 and with a suggested Porb of
0.066 days, it's a good target for superhump fishing.  A prime choice in
the southern sky.  It's called "Dor" (as well as CAL 86) in the CV Cat,
with 2000 position 5 46 15.26 -68 35 24.1.  Need long runs, especially
since the published spectroscopic period appears to have some aliasing

XZ Eri is long gone, so delete that one.  (Of course, you did so long

We have another Kitt Peak run coming up (March 10-24), and will probably
work hard on DW Cnc.  I think that means PQ Gem and V405 Aur are the
best other northern targets for the next few weeks.  As DQ Her stars,
they'll reward even short observations - but we most earnestly want to
study the issue of superhumps in these magnetic variables, a subject
still quite unexplored.  So some decent length to the time series would be
mighty nice.

In other words, I guess we'll take over on DW Cnc from here on.

The 20-dwarf nova paper is almost ready for submission...


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