stars of the moment

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Mon, 8 Feb 1999 11:48:00 -0500 (EST) · jop_at_astro.columbia.edu

Dear CBAers,

Re starry targets, there are big developments to report.  For
northerners, the very very scattered coverage so far indicates that
BK Lyn (= Cnc 1 = PG0917+342) has probably jumped to a new period
and greatly increased its amplitude.  Thus it's now the best target
for all northern scopes.  My guess at this early date is that it's
imitating the act V603 Aql performed in 1994.  But we can much more
satisfactorily study this phenomenon now, because our tools are better
now, and because there's a big difference between February nights and
July nights!

The best comparison star appears to be the star 2' ESE from the variable,
near the little background galaxy.  This star has V=13.22, B-V=0.94
according to Henden & Honeycutt.  Not our favorite color, but the best
overall choice I think.  You should get Var-Comp values around +1.7
in unfiltered light with a red-sensitive chip (like practically all 
CCDs).           

Another star that we're studying closely is DW UMa, which dived into a
low state a few weeks ago.  Nice target for the biggest scopes, which
can perhaps resolve the time scales around the eclipse (18th-20th mag).

For southerners, our old friend Men 1 = AH Men has just thrown us a
curve ball (Kiwis please translate to the cricket equivalent).  For 4
years it always tossed at us a complex spectrum of periods near 3
hrs: at 2.95, 3.05, and 3.30 hrs.  Usually two were simultaneously
present, accompanied by complex harmonics.  During December 1998, we got 
extensive coverage from Piet Meintjes in South Africa and Marc Bos in
New Zealand, and some from Jonathan Kemp in Chile.  Can't argue with
that longitude coverage.  Great was my chagrin when a first pass at 
the data showed *no* convincing periodic signals near 3 hours!  Some 
of the familiar harmonics were weakly present, and Piet may be able to
dig out our old friends after a close look, but the overall outlook was
disappointing.

The moral I suppose is that even the "permanent" superhumpers need to rest
every so often.  Fair enough; I just wish they wouldn't rest during a 
multi-longitude campaign.  And the other moral is that we should avoid 
this star for a coupla years.  Let's get friendly instead with the other 
bright short-period CV in the southern summer sky - RR Pic - and also
start the year up on SW Sex (note the coords of this star in DWS are
incorrect in the RA listing, but correct in the alphabetical listing; 
there's a chart and a comp and good coords in ye olde CBA website).

Finally I'd be interested in hearing your plans for attendance at the
PASP meeting in Toronto, which several of us will attend and even have
a little CBA table.  Personally I also plan to attend the previous week's
photometry conference in New Zealand, where we have accumulated such a 
strong network despite my never having met any of the people involved.

We just revised the website a bit - with BK Lyn flashing to remind you!

          Joe