(cba:news) stars for mid_january

Joe Patterson jop at astro.columbia.edu
Sun Jan 10 17:23:40 EST 2010

Dear CBAers,

Time for some target changes.  We've been conducting a long campaign on 
XSS0056+45, and by now all the periods (spin, orbit, various sidebands 
and harmonics) are well specified - and over a 54-day baseline.  These 
periods will only slightly tune up from now on - so let's usher XSS off 
the stage.

Likewise for RX0704+26.  David Boyd sent a few nights of European data, 
breaking the alias, and steady coverage from Mike Potter, Bob Koff, and 
Tom Krajci has extended the baseline and enabled a cycle count going 
back to discovery 5 years ago.  Even a comparison of X-ray and optical 
phases.  So, again, all the period-finding  is done... and, unless the 
star decides to erupt or fade or otherwise surprise, let's end the campaign.

These winter campaigns on DQ Hers are going well; let's keep going!
An evening pulse-timer target we haven't observed in several years is 
V709 Cas; it would be awfully good to get some late-season timings.  The 
period is 312 seconds, so keep cycle times below ~80 s.  The other stars 
are suitable for pulse-timing too, but their favorable placement in the 
sky makes them suitable for longer runs (which give better timings, and 
also can reveal other periods):  these are HT Cam, Swift 0732-13, DW 
Cnc, and WX Pyx.  All good targets.  Plus EI UMa = PG0834+48; somehow 
we've never done a campaign on that one, but some fair evidence has 
emerged that suggests its identity as a DQ Her.  Let's find out!

Finally, there are the two AM CVn stars on our long-term list: ES Cet in 
the evening sky, and AM CVn in the morning.  Not quite the right season, 
but good investments in the evening and morning.

I'm back in NYC now, and good heavens, beginning a sabbatical!  I should 
have much more time for science and CBA biz this year.


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