From jop at astro.columbia.edu  Sun Mar  5 10:38:30 2006
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sun, 5 Mar 2006 10:38:30 -0500 (EST)
Subject: (cba:news) SDSS080434.20+510349.2 is 4.5 mag brighter (fwd)
Message-ID: <Pine.GSO.4.33.0603051036340.14108-100000@fidelio.phys.columbia.edu>


Dear (northern) CBAers,

I just received this from Elena Pavlenko.  It sounds mighty interesting,
and is mighty current!

Have a shot at it!

joe

---------- Forwarded message ----------
Date: Sun, 5 Mar 2006 15:05:41 +0200
From: Elena Pavlenko <pavlenko at crao.crimea.ua>
To: Joe Patterson <jop at astro.columbia.edu>
Subject: SDSS080434.20+510349.2 is 4.5 mag brighter

Dear Joe,

Last night (March 04/05), starting BVRI
photometry with 2.6-m Shain telescope of the
Crimean astroph. obs. at ~19h UT,
I found CV SDSS 080434.20+510349.2 at 4.5 mag
brighter than before. Accordingly to P. Szkody,
this object was 17.9 - 18.3, its spectroscopical
period 1.42 hrs is twice the photometrical one
(42.5 min). During ~0.2-d time interval this
object could display fast 0.5-mag brightening,
the 42.5-min oscillations increase their amplitude
from 0.05 mag to 0.2 mag!  At another time
this star could show no brightness oscillations.
No brightenings/outbursts were known so far
for this object. During this bright state
over ~4 h duration the star displayed both oscillations
and quiet state, and mean brightness remained stable.

As long as it is 14th mag star, it is  accessible
for the amathor observation!

Elena Pavlenko



From jop at astro.columbia.edu  Sun Mar 12 07:42:14 2006
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sun, 12 Mar 2006 07:42:14 -0500 (EST)
Subject: (cba:news) mid-March stars
Message-ID: <Pine.GSO.4.33.0603120716530.21797-100000@fidelio.phys.columbia.edu>


Dear CBAers,

Time for another round-up of once and future loves among the CVs.

Two stars to delete from the menu (you did anyway) are RX0022+61 and
SDSS0804+51.  By virtue of sunlight and return to quiescence, these stars
are retired for the year.

Little Swifty (Swift0732-13) is going great guns: still lots of great data
coming in from NZ, and from Arkansas too.  A recent ATel resolved the star
into two - a faint blue star which is the true Swifty, and a crowding star
1.8" away which tends to dominate at R and I (and explains the apparent
flatness of the raw light curve).  This is not a huge nuisance to us since
the periodic variations are more or less different to contamination by a
constant light source... but if you happen to have a blue filter, that
would be helpful!  Otherwise, just carry on for a couple more weeks.

It's getting a touch late for DW Cnc, but I very much want a few more
weeks of coverage - to nail down the somewhat subtle periods for the year.
A good evening target for borealites.

I had great hopes for RX1039-05 and WX Pyx a month or two ago.  These are
admittedly quite faint stars (17-18) but the periodic signals are VERY
LARGE, and I'm guessing that many of you guys can get quite acceptable
data if the skies are clear.  Still around for another month or two - give
it a shot.

The other faint star I wanted to endorse is RX1050-14, available to both
hemispheres.  I don't promise much for this guy though - its photometric
signals are pretty weak.  If it erupted it would be ENORMOUS news - so
keep an eye on it.  A few get-acquainted time series would be good too.

The bright targets for the two hemispheres are these.  WX Cen in the
south; we'd like to evaluate it for membership in the supersoft-binary
class.  And AM CVn in the north.  This is the beginning of what I expect
will be a long season of AM CVn coverage.  My main goal is to study the
weak orbital signal (1028 s), which past data suggests is shortening on an
astrophysically interesting timescale.  I'm pretty sure that a final
season's coverage will nail this result down.  It's also true that this
star always throws surprises at us - let's keep a close watch and keep
ourselves open to those surprises!

I'll write again in a few days.  A week off from the pressures of classes
and exams - what a pleasure!

joe




From jop at astro.columbia.edu  Fri Mar 17 22:59:40 2006
From: jop at astro.columbia.edu (Joe Patterson)
Date: Fri, 17 Mar 2006 22:59:40 -0500 (EST)
Subject: (cba:news) week's vacation...
Message-ID: <Pine.GSO.4.33.0603172246400.28052-100000@fidelio.phys.columbia.edu>


Dear CBAers,

In a few hours I'm going off for a week's vacation, and it's unlikely I'll
have email access.  So I'll be basically unreachable... and when I return,
unless spammers also go on vacation, I'll have >1000 unread messages.
Between that and classes it'll take me till next Saturday/Sunday to come
up for air.  If you have something urgent, send to Jonathan - he never
has anything to do.

The target list seems fine to me - except that I urge again that people
in both hemispheres take a crack at RX1039-05 ("Sex").  It's pow'f'l faint
but should come roaring in with its very large amplitude variation.  A
tougher target is RX1050-14 ("Hya").  Tom Krajci has been getting some
good data from it, but we really need southern data with the longer nights
and the longitude spread.  I grant that the light curve will look like
nothing at all - but expect we will be able to extract the critical (and
subtle) orbital variation.

Have a week of clear nights!

joe