(cba:news) valentine stars

Joe Patterson jop at astro.columbia.edu
Fri Feb 15 17:58:01 EST 2002

Dear CBAers,

Well the cast of characters is changing fast.  Series of one-act plays
goin' on up there.

HT Cas fell back to quiesecence.  Back to obscurity for it.

BH Lyn.  She loves me, she loves me not.  The star tantalized with some
waves and level shifts (0.3 mag very slow variations).  We got 26 of 32
nights covered, with a good range of longitude.  We'll *probably* pull
periods out of this, but it'll take some work - too much work to invest in
weak results.  The 1997 campaign also gave a tantalizing but not quite
decisive result.  If the two tantalizers are consistent, then we're in
business.  Anyway, I don't want to invest any more in this coquettish
star, since there are some great performers nearby in the sky.

Namely, BK Lyn and DW UMa.  We should keep up pressure on these stars for
a long time.  They're both showing *big* negative superhumps + nodal
precession periods of a few days.  Since DW UMa eclipses, it provides
the opportunity to map the spatial extent of the superhumping light
source... a pretty nifty trick.

I'm *really* hoping for long European or Asian coverage of these stars,
as that will enormously aid in defining the daily light curve.  We get 9
hours from North America, but lust for more!  Arto, you still out there?
How about one bronze medal in X-country skiing for 3 nights on DW UMa?

In the far south, there's EC05114-7955.  Definitely the one to keep the
pressure on... and I'd be grateful for whatever you can get on T Pyx
(anyone sentimental about the old-timers?).  We're trying to get a
seasonal timing of T Pyx, it needs about 30 hours of coverage.

Finally there's PQ Gem, making its debut in these pages.  It's a DQ Her
star, therefore definitely one of our boys.  But its 13 minute pulse is
*color* dependent, unlike virtually everything else we study.  So it's
awkward to do in white light - hard to interpret the results.
Nevertheless, I'd like to run a campaign on it right now in the evening
sky.  We're doing it in BLUE light at MDM right now, so your own
observations, effectively something like R, will provide "multiwavelength"

Happy observing!


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