(cba:news) stars for july-aug

Joe Patterson jop at astro.columbia.edu
Tue Jul 26 09:16:56 EDT 2011

Dear CBAers,

Sorry for my long silence.  While on vacation I had some minor injuries 
falling on the rocks in Maine (arms, hands, fingers - made typing a tad 
difficult).  You don't notice the cold of the water so much when you're 
dumped unceremoniously into it.  But it was otherwise a fine vacation!

CBA data has also slowed, partly due to the summer monsoon in the 
southwest USA, except for Berto and Tut Campbell/George Roberts, who are 
unstoppable.  We are still trying to track V1432 Aql, a fine target with 
lots of action and an eclipse.  It's an "asynchronous polar", with Prot 
and Porb slightly difference - and with the difference (allegedly)
slightly decreasing with time.  This process of "relocking" magnetic 
white dwarfs is a fascinating piece of physics, which it's up to 
observers to constrain.  That would be us.  Unlike most of our targets, 
there's no great advantage in every-night coverage.  Occasional visits 
spread out over the observing season are fine.  The beat period is 50 
days, so every 5th day gives good definition of this cycle... and we'd 
like to get 2 cycles (100 d) during a season.

V1432 Aql was once a mega-celebrity object, thought to be the only AGN 
with a strict period.  Then a CV was found right next to the AGN; the 
AGN was greatly demoted in status, but the newly-discovered CV became a 
minor celebrity in its own right, because it joined a really tiny class 
of CVs, and became instantly the best-observed such object (partly 
because of all the prior data taken under the AGN banner).

V1974 Cyg, was an even greater celebrity, called "the nova of the 
century" (1992).  I think it probably deserves this title, though it's a 
touch unfair since soft X-ray and infrared detectors didn't get a peek 
at the great novae of yesteryear.  Anyway, it's still hanging in there 
around 16th magnitude, flashing definite superhumps.  This is a somewhat 
challenging star (faint, crowded field), but still accessible to many 
CBA scopes.  Great target if you're up for something hard (good sky and 
telescope conditions needed).

The other two old novae we're trying to put to bed for the year (and 
finish papers on) are V1494 Aql and V4743 Sgr.  Also around 16th mag, 
and both with strict - well, probably strict - periodic variations. 
Along with V1974, each of these stars would reward *intense* study - 
long observations spaced over consecutive (as close as possible) nights.

As usual, I'm hungry for time series of DQ Her stars.  V1223 Sgr is an 
easy target but has been neglected this for the past 2-3 years.  V2069 
Cyg needs some help, as does RX2133+51 and V2306 Cyg.  All highly 
seasonal.  In the morning sky, IGR0023+61 and V709 Cas (tough target, 
low pulse amplitude).  These targets are basically suitable for
once-every-few-nights, though would somewhat profit from one denser data 

Finally, there's V455 And - the star that never fails to delight (but 
also never relaxes enough that you feel it's time to write the paper).
Can you possibly get 15 s time resolution on this 16th mag star?  If you 
can, I'd be eternally grateful!  (For the data, not just that you could 
do it.)

Enrique de Miguel is spending the summer with me in NYC, and Jeremy 
Shears is visiting both of us next week.  Good opportunity to connect 
with far-flung CBAers, even without leaving home!


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