(cba:news) springtime stars

[Joe Patterson]

Dear CBAers,

Time for some changes up there.  Northerners have leapt into the breach on
UMa6, and southerners on WX Cen.  We have very high-quality mean light
curves for these eclipsing stars, and we can basically quit for the year.

I'm still anxious to pick up EC10578-2935 before it recedes too far to the
west.  However, the signal is subtle and the star not so bright for the
bright-moon conditions coming on.  If you can get long runs of quality on
it, that's a very good target.  There are three other southern targets to
mention:

BR Lup - presently bright (superoutburst) and showing nice humps.  Great
target for the next 10 days or so.

EX Hya.  A venerable star, but oddly never the target of a CBA campaign.
It is time to remedy that oversight!  Well positioned for all southerners,
and some folks in the southern USA as well.

Finally, IM Nor.  Woudt and Warner just published a little paper
announcing the orbital period - 2.5 hours, just the second short-period
guy found among the recurrent novae.  The mean mag is 16.5 and the
modulation is only 0.10 mag or so... but I know from experience that this
is the kind of wave we can easily track, since it is almost exactly like T
Pyx in all these respects (just 1 mag fainter).  Let's tighten up that
orbital period!

In the north, away with UMa6, and also DW Cnc and PQ Gem - their seasons
are basically over.  BG CMi is still timely, and CR Boo and EX Hya.  The
main northern stars I wanted to hype are HZ Her and V533 Her.  The latter
is showing a very stable QPO - disturbingly stable for a process
generally regarded as incoherent.  This needs much better documentation.
And just as we have criminally neglected EX Hya over the years, HZ Her is
another star that should have been on our lists for many years.  So let's
launch that campaign pronto.  I'll write later in the week re comp stars
and such (but some of you might want to write to "news" and recommend
some)

Lotta teaching this week - back to the trenches!

joe