(cba:news) stars for November-December

Joe Patterson jop at astro.columbia.edu
Mon Nov 25 22:47:17 EST 2013


A non-text attachment was scrubbed...
Name: cba1125.pdf
Type: application/pdf
Size: 34320 bytes
Desc: not available
URL: <http://cbastro.org/pipermail/cba-public/attachments/20131125/f09e3cea/attachment.pdf>
-------------- next part --------------
Dear CBAers,

First school vacation all fall. Time for revising the menu. 

V513 Cas and IW And.  Time to stop.  I think everybody has... but just in case.

OT0057+44.  Still a good target if you can reach it (17-18 now) with decent S/N.

VZ Scl.  We have about a 45-day baseline now. The star has eclipses (of course), a powerful negative superhump, and something else I can't quite decipher.  It could be a positive superhump, which beats with the negative guy and thereby changes the hump amplitude... or it could be just an intrinsic amplitude modulation in the negative guy.  Or something else altogether.  But I think it's just too late in the season to tell for sure.  So let's close it down for the year, and resume next August!  Josch and Bob Rea have really done yeoman service on this star, with some critical runs also by Gordon Myers.

AQ Men.  Great southern target. Our recent MNRAS paper (Armstrong et al.) demonstrates something quite unusual in this star.  In addition to negative superhumps (which I suppose should no longer be considered "unusual"), the star seems to have *variable* eclipses - occurring on a precise period, but with a profile that varies a lot.  Is this variation cyclic, and if so, is the cycle time equal to the beat period between orbit and superhump?  Let's find out!

AH Men.  I wrote a paper on this far-south star back in 1995, based only on data from Chile.  But there were zero southern CBAers then, and we can do so much better now. It's a bright star and a respectable SW Sexer, with a light curve complicated by the simultaneous presence of negative and positive superhumps (I think), and by the presence of an annoying intruder star about 4 arc-sec away.  If you can get photometry by excluding that star, then fine.  But most of you would likely prefer including it, and then subtracting its light (assumed constant).  If the latter, then
you might want to observe in BLUE light, where the CV is substantially brighter than the intruder.  AH Men is bright enough (~13) to survive the filtration.  Settle on one of these strategies, then stick with it; that's the usual CBA prescription.

V902 Mon.  Shiny new intermediate polar, eclipsing, equatorial.  Just an all-around great star - let's try to follow it around the globe!

BY Cam.  Now's the time to resume lengthy runs on this well-placed star.  It's up to us to measure this star's slow rate of spin-up.  Someone's gotta do it!  Easy northern target.

A couple miscellaneous hunches: LS Cam and BZ Cam.  Tantalizing...we've never quite figured out what these stars are.  BZ Cam is very bright and would be a good small-scope target for long runs.

A few well-placed DQ Her stars: V647 Aur, V418 Gem, HT Cam, BG CMi, MU Cam,
V667 Pup.  Short (2-hour) runs usually OK, but long is always better.  Then there's IGR 0457+4527 (Masetti et al. 2010: 04 57 6.98 +45 27 48.5), a 17th mag DQ Her guy which has not yet been properly published.  *Great* target if you can go that faint.

joe p

P.S. I hope people are thinking at least a little bit about the upcoming SAS/AAVSO/CBA meeting at Ontario (CA) in June.  
-------------- next part --------------
____________________________________________________________
Center for Backyard Astrophysics (CBA) mailing lists
http://cbastro.org/communications/mailing-lists/ 


More information about the cba-public mailing list