(cba:news) U Gem in outburst

Joe Patterson jop at astro.columbia.edu
Mon Jan 15 19:28:06 EST 2007

Dear CBAers,

U Gem is reported to be in outburst tonight (10.7).  For many years I've 
wanted to get long CBA light curves of the star through an eruption 
cycle.  This is a great chance to start, since the star is well-placed 
now and will remain so for the next 100 days!

The main purpose is to study the shape, size, and exact location 
(timing) of the bright spot eclipse.  As a secondary goal, it will test 
for the presence of superhumps (the literature is conflicting on this 
one) and for the presence/return of the orbital hump.

U Gem is a beautiful test object for the theory of bright spots, because 
the eclipse is so precisely oriented - the spot is eclipsed but not the 
white dwarf.  Fire away!

10.7 is a bit measly for a U Gem eruption, but it may brighten... and 
anyway, 3.5 mag of dynamic range is plenty enough lever arm to obtain 
some really nice scientific results.

As you settle down to observe it, investigate the local comp stars and 
recommend one that most CBAers can use.  I've not observed U Gem in 22 
years, and my notes are long gone...


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