(cba:news) V1084 Her, no; V503 Cyg, V1432 Aql si; plus the DQ Hers

Joe Patterson jop at astro.columbia.edu
Thu May 31 17:11:08 EDT 2012

Dear CBAers,

A few notes before starting my trip home.

I've studied the V1084 Her data (mostly Tom).  Flickers like crazy, but 
the periodic signal was invisible despite the very good quality of the 
data.  Time to quit.

Let's start the season on V503 Cyg and V1432 Aql.  For the latter, an 
asynchronous polar, we're trying to measure the changing period of the 
photometric wave that signifies rotation.  That will yield the timescale 
for synchronization - thought to be a few hundred years, but not 
decisively specified by observation.  It takes pretty long seasonal 
coverage to completely rule out cycle-count ambiguities - so let's 
start!  You probably need 3-hour time series, but there's no great 
advantage in going longer.

The same type of program is appropriate for V503 Cyg, but of course the 
motivation is vastly different.  It's a borderline ER UMa star, and 
likely to erupt in the next 2 weeks.  We especially favor time series in 
superoutburst (positive superhump guaranteed) and quiescence (negative 
superhump very likely).  The fast up-and-down stuff the ER UMas 
sometimes throw at you - usually in the range 15-16 - is of lower 
priority; it can be hard to extract periodic signals during these 
phases.  In fact, it would be very good to keep a close eye on the THREE
borderline ER UMa guys: V503 Cyg, SS UMi, and IX Dra - and send any 
detection of (super)outburst or deep quiescence to cba-chat.

And it's the season for DQ Hers.  Everyone observing these should become 
familiar with Koji Mukai's intermediate polar web-page.  It lists all 
the stars, with lots of useful info.  Pick out a nice star for your 
latitude and time of night, make sure it's optically bright enough (they 
mostly are, but check to be sure), and get a 2-3 hour light curve. 
Unlike our usual programs, there's no great advantage in concentrating 
on one star for many successive nights.  Spread the wealth - the purpose 
here is to establish a long-term O-C, so steady light pressure on these 
stars is just fine.  BTW add one important one to the list: RXJ1654-19. 
  And I hope australites will nail EX Hya for a final end-of-season 


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