(cba:news) more on AY Sex

Joe Patterson jop at astro.columbia.edu
Thu Apr 24 16:31:22 EDT 2014


BTW I sent incorrect coordinates.  38, not 48!  So the correct 
coordinates are 10 23 47.687 +00 38 41.15.  Whew.

Best to observe unfiltered, since it's the activity level we want to 
study (and compare with other wavelengths).  But a few integrations in V 
light would also be good, to establish the star's calibrated V 
magnitude.  Usually a good general rule, by the way.

 From the light curves I sent, note there seems to be a pattern of a 
slow sinusoidal wave - perhaps the result of the heated secondary - plus 
"positive flickering" (only upward excursions from the 4.8 hour orbital 
wave).  The latter is alleged to be from the rapidly spinning neutron 
star.  Let's see if this explanation holds up.

When you know the approximate V brightness, send it in!  HST, or a gang 
of humans running it, is always nervous about these active binaries 
frying their detector.

joe p
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