(cba:news) CR Boo and UMa transient

Joe Patterson jop at astro.columbia.edu
Fri Mar 31 10:27:25 EST 2000

Dear CBAers,

     We're enjoying a fine early spring in the Northeast - just about 
average for clear nights, but great for golf and baseball.  Much
treasured by those of us living in concrete jungles!

     We got pretty good response on DW UMa - from Dave East, Cap'n Bob,
and Brian Martin.  But the star disappointed - no big superhumps like it
showed in 1996 and 1997.  Time for us borealites to move on.  Then a
couple of days Ron Remillard announced a new X-ray transient in UMa
(where there sure are a lotta fireworks this year), and optical ID from
Uemura and Buczynski has pinpointed the position: 11h 18m 10.79s, +48d
02m 11.2s (2000.0).  It appears to be about 13th magnitude.  Let's get
cracking on this guy, it's definitely the object of choice for northern
telescopes now.

     Until the UMa transient, I wanted to kick off the 2000 all-site
campaign on CR Bootis, which at 1346+08 is well-placed for everyone now.
John Thorstensen will obtain spectroscopy in a week's time, so I wanted
to start the photometric campaign now, and go for about six weeks.  We
did a fair job on CR Boo in 1996, but that was before we established 
a strong node in NZ.  Now we can do much better in terms of global 
coverage, which is essential here because the putative dwarf-nova cycle
is about 18 hours.  Then the UMa transient came along.  Here's a 
compromise: could the southern observers start the campaign now, and we 
in the north will do CR Boo as a secondary target?  That way we'll get
some global coverage now, to be simultaneous with spectroscopy, and will
switch to all-site coverage when the bloom is off the UMa rose.

     I have to admit, it might be a little dangerous to switch off V803
Cen so soon.  But as Stan (and Andrew Pearce) recently remarked, it seems 
to be doing its up-and-down cycling thing - and we've already documented
that pretty well.  We know a lot less about CR Boo, and we could know a
lot more, since it's accessible to all of us.

     Fred Velthius and Jennie McCormick sent some nice data on VZ Pyx,
which I haven't yet been able to study thoroughly.  I did study the amazing
Kiwi data on OY Car, which form one of the finest records of a dwarf-nova
outburst I have ever seen!  I'll send some of that as soon as I get out of
class this afternoon.

     UMa transient and CR Boo - pretty simple this time!


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