(cba:news) october-november stars

Joe Patterson jop at astro.columbia.edu
Wed Oct 24 10:06:05 EDT 2007

   Dear CBAers,

   Well, the flow of data from the V455 And has been immense, and of
   a quality which should be sufficient to define the properties of the
   outburst quite well.  I've been kept busy tracking everything day by
   day; our data illustrate the various changes in eclipse shape and in 68
   s pulse phase (which stays pretty constant, although has to be
   studied mainly by using the 34 s first harmonic).  To a first approxi-
   mation, it seems that the pulse phase charges right on through the
   outburst, as if nothing is happening!  This is more or less what you
   expect if the signal represents the spin period of a rapidly rotating
   white dwarf. Soooo..... I guess it does!

   That's good enough for me. I think it's still very desirable to obtain
   long nightly coverage of V455 And - for another month or so.  But
   the frantic search for better time resolution - well, we can call that
   part off.  Cycle times of 30-40 s probably suffice to define the other
   fine detail of the light curve: the variable eclipse shape.  This is
   of very great interest; if you've been covering it, keep it up!

   BTW are there new V455 And time series (from the last 10-15 days) in
   the pipeline?  I suspect there's some European data on a slow boat....
   I'm hardly ever concerned about this, but I wanted to fast-track all
   this data, and it would help a lot to prepare FINAL nightly light

   The other prime northern target is RX0022+61 = IGR0023+61 = "Cas".
   We got a boatload of coverage last year, but not quite enough to solve
   all the aliasing (and borderline signal) issues.  This is an excellent
   target for all-night photometry over the next six weeks.  BTW this is
   NOT the same star as V410 Cas, which lurks dangerously nearby.

   Later on in the northern nights, new and hardly-studied DQ Hers come
   into view.  I highly recommend RX0636+35 = "Aur" and RX0704+26 = "Gem".
   Plus V405 Aur, an old friend we haven't visited in years.  Peachy
   targets for those brisk, clear mornings of October and November.

   The Milky Way's in the far north now, so the pickings aren't quite
   as abundant in the south.  Here's the big three that I see.

   (1) BW Scl.  The southern V455 And.  Just as rich in periodic
   signals, no eruptions yet known. About 16.5, so perhaps will need
   a fully clear night.

   (2) RX0232-37 = For (but I believe not in Downes et al.).  Seemingly
   another WZ Sge star... but the light curve has new surprises (it's
   rising again), and the superhump endureth.  Might not erupt again in
   your life.

   (3) SDSS0407-06 = Eri.  A great, great negative superhumper, or at
   least it was 2 years ago.  I'd like to run a big campaign in December
   from both hemispheres.  But early-season data now would be mighty nice.

   Happy observing!  I hope to see a few of you next week in Cambridge
   (AAVSO meeting).



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