(cba:news) stars of the month

Joe Patterson jop at astro.columbia.edu
Thu Jan 16 11:37:49 EST 1997

Dear CBAers,                                          Jan. 16, 1997.

     Well, I studied the EG Cnc data some more and see that this is
probably the most interesting superhumper of all the dwarf novae.  For
the first two weeks, it was pretty much ho-hum, oh-yes-another-one-of-
those.  But now it's evident that the humps have been severely affected
by the secondary outbursts that have punctuated the decline.
Unfortunately this means that we need extensive coverage through
these outbursts, which we're not getting.  If the star continues to
burp and the superhumps continue, we can probably atone for this;
otherwise we'll try to join forces with some other EG Cnc observers, in
order to define the waves properly.

     So I wanted to re-promote this star as co-equal with (or better
than) BH Lyn in the coming 12-day period.  We desperately need more
data.  Alon, I strongly think you should try to do EG Cnc as well as BH
Lyn during your run coming up.  With average or good weather I believe
we can get enough data to solve the important 24-hr aliasing and fine-
structure issues for both stars.  I also recommend unfiltered operation
in both cases.  For BH Lyn, it's because we have a great deal of
interest in the exact shape of the eclipse; that's what will constrain
the shape/size of the disk.  I think we need the extra counts to define
the light curve better in eclipse.  For EG Cnc, it's mainly because the
star is 16th mag out of outburst (likely to fade further too).  I
recommend spinning the filter wheels once at the beginning and end
of an observation, to help calibrate the magnitude levels better.

     Meanwhile, the Moon waxes onward.  Sorry about that.  Try somewhat
longer exposures if the stars are too faint for you (especially the
small-scopers) -- assuming the drive quality is up to snuff.  Let me 
know what you manage to get!


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