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    january targets

    From: Joe Patterson <jop_at_astro.columbia.edu>
    Date: Thu, 15 Jan 2009 21:50:08 -0500
    Dear CBAers,
    
    Sorry for letting the current targets get a little brown around the 
    edges!  I've been taking advantage of the Xmas break to write up papers, 
    and have been keeping up with the data you've sent.  But the eruptions 
    have faded, the year has turned, and... time for a new menu.
    
        Dwarf nova eruptions are by their nature unpredictable, and the most 
    interesting ones are faint and mighty rare.  So these are, at least for 
    now, in abeyance.  Every January, though, a host of DQ Her stars rolls 
    around in a good sky position.  We haven't seen any of 'em in 8 or more 
    months, so they're all ripe for sharpening the period measurement 
    (through lengthening the baseline).  *Both* periods - rotational and 
    orbital... with an outside chance of another one (superhump or some such 
    thing) jumping up and saying hello.
    
        The fairly easy stars to do (no great challenges in terms of 
    brightness) are:
    IGR0023+61 = RX0022+61
    V405 Aur (0558+53)
    RX0625+73 = MU Cam
    RX0636+35 = "Aur"
    BG CMi (0729+103)
    
    The slightly harder stars to do are:
    RX0704+26 = Gem
    Swift0732-13
    DW Cnc (0758+16)
    
    Now our usual strategy for practically all stars is to stay on one 
    target all night long (or substantially all night).  That always gives 
    the best chance of finding something altogether new.  And in this case 
    that might be true too - adopt a star and stay on it for two weeks!  But 
    strictly for the purpose of accumulating pulse timings - and thereby 
    tracing out the long-term period change, it's better to knock these 
    stars off in little 3-hour segments, jumping around the sky from star to 
    star.  Then it might be feasible to track most or all of the targets.
    Take yer pick!
    
    There are a few exceptions to this call for a long assault on the DQ Hers.
    
    1. T Pyx. I'm just finishing a paper on the 1998-2008 timings.  It would 
    be nice, and easy, to fold in the 2009 timings.  About 2 weeks of solid 
    observation will no the trick.
    
    2. V436 Car. This continues to haunt me.  We've had one decent campaign, 
    but never a really good one.  The star has a very, very high proper 
    motion , suggesting it's very nearby.  But we still just haven't figured 
    out the periods.  Perfectly timed!
    
    3. AM CVn.  Same comment as T Pyx.  But unlike T Pyx, it's still just a 
    touch early in the observing season.
    
    And lots of CBA correspondence to catch up on. That's what tomorrow is for!
    
    joe
    
    Received on 15 Jan 2009