New and old stars

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Mon, 13 Oct 2003 11:55:31 -0400 (EDT) · jop_at_astro.columbia.edu

Dear CBAers,

Lotsa progress lately.  Time for some reports.

The 20-star paper just came out in PASP (Nov 2003).  The preprint version
is posted on the CBA website, and differs only slightly.

V551 Sgr and RU Hor are dwarf novae that have run their course.  Exit
both.  Now we hope to find their *orbital* periods through some other
means.

The campaign on V1101 Aql, primarily waged by Dave Messier and Tom Krajci,
is going great guns.  This star has a very strong 3.9 hour signal, and
something else at low frequency that may or may not be periodic.  It has
the whiff of a negative superhump.  With continued coverage, we'll know in
a few weeks whether that low-frequency thingamabob is stable, and also
whether Pspec agrees with Pphot.  Superb target for northerners... but
very nice for australites too, because even quite brief time series will
fill in critical points in the long-term light curve (i.e. elucidate the
low-frequency activity).  Wonderful star!

DI Lac and Cyg 1.  Unnhhhh.  These stars tantalize but haven't yet
delivered the goods.  I think they should be swept off the stage, unless
the spectroscopists (I assume John) sweep them back on.

OR And.  That was a very nice campaign, with many participants (Foote,
Fried, Krajci, Skillman, Novak, Oksanen, Cook)... and gave a very clean
signal at 0.1359(1) d.  Probably that's Porb, though it still awaits
confirmation from spectroscopy.  We got a 20-day baseline and pretty
dense coverage; that's enough.

MANY new northern targets swing into view in October.  I dunno why
(unlikely things happen!) but there are a host of DQ Her stars
(intermediate polars) and candidates in the general vicinity of 5h+60 deg.
These are red meat for CBA studies.

I guess the two best are:

Cam    RX0625+73
FS Aur   0547+28

"Best" since they are certifiably interesting, somewhat unstudied, and
offer a strong periodic signal for study.

More speculative are:

Cep     0506+83, or HS0455+8315
Aur2    0614+45

Not much known yet about these guys.  The latter has a fast periodic
signal (87 min) reported, but it was weak (just 1%)... so would need a
*lot* of coverage.

And V405 Aur.  A definite DQ Her star... but very strong oscillations, and
with no good study of Pdot or detailed period structure, it's time for us
to remedy this.

So a great month for the north.  The best star for long coverage in the
south now is AH Men.  We have a big storehouse of data wanting to come
out... and one more year of coverage will definitely bring it out of
hiding.  Very, very rich spectrum of periodic signals, and a *bright* star
(12.7 or so).

AO Psc and FO Aqr continue to be good for any hemisphere you might happen
to think of.

joe