CR Boo and ASAS J1536-0839

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Tue, 04 May 2010 03:55:33 -0400 · jop_at_astro.columbia.edu

Dear CBAers,

I've heard now from Enrique de Miguel Agostino and John Thorstensen 
regarding these stars.  ASAS 1536 ("Lib") is about 18.4, and unless 
you're distinctly enamored of working on such faint stars (some people 
are), I'd advise you to take that one off the list.

    On the other hand, Enrique estimates "fainter than 17.0" for CR Boo 
- and for us, that really vaults the star in priority.  We've observed 
CR Boo for hundreds of nights, and only found it faint (~17.5) once... 
and when we did, it showed a really strange spectrum.  I've been craving 
for this opportunity since 1996.  Also, give the star now a high 
priority after it leaves the low state (sadly, that'll probably be quite 
soon); exactly how the star enters and leaves the low state - relative 
to its normal state of rapid cycling, for example - is unknown.  Because 
past observations suggest a cycling quasiperiod around 19 hours, the 
star will GREATLY repay multi-longitude observation.  With an equatorial 
location and the star now transiting near local midnight, this is likely 
to be a great observing opportunity.

    17.5 might well be too ambitious, and if so, have a high old time 
with HP Lib - a close relative, quite bright, and pretty interesting 
too.  But we'd sure love to indulge this craving for CR Boo in quiescence!

joe

John, I know yer out there with a spectrograph and a big telescope... 
and it's near local midnight.  And reading email at this exact moment. I 
fling down the gauntlet.