From jop at astro.columbia.edu  Wed Oct 19 12:16:43 2011
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 19 Oct 2011 12:16:43 -0400
Subject: (cba:news) v1432 aql and cp eri
Message-ID: <4E9EF7EB.60202@astro.columbia.edu>

Dear CBAers,

A couple of objects to take off the menu: RX2133+51 (until December, 
when it's time for late-season pulse timings) and DQ Her (until Feb-Mar, 
when it's time to start up the new season).  These stars have been 
getting great coverage from Tom, Enrique, Etienne Morelle, Jim Jones, 
and Tut/George (I can't tell 'em apart since the data flows through George.

Here are two new ones:

V1432 Aql.  We more or less concluded our season... BUT Suzaku (an X-ray 
satellite) will be making a long observation in late October, and they 
need timings of the eclipse (which should be easy) and the 
not-quite-synchronous wave (harder, but multi-longitude should permit 
it).  That's our job.

CP Eri.  We got some great data on this helium star in 1998 (oops)... 
which we're now readying for publication.  It's about 19.8 in 
quiescence, so I don't expect anyone to salivate at that.  However, its 
eruption (to 16.5) frequency is unknown, and I suspect it erupts a lot. 
  When it erupts, drop everything you're doing, and follow it 
tree-to-tree with time-series photometry. (and send to cba-news, -chat, 
Goodyear blimp, etc.)

joe

longer message tomorrow


From jop at astro.columbia.edu  Fri Oct 21 07:47:14 2011
From: jop at astro.columbia.edu (Joe Patterson)
Date: Fri, 21 Oct 2011 07:47:14 -0400
Subject: (cba:news) BW SCL bright outburst  (v=9.6)!
Message-ID: <4EA15BC2.2030700@astro.columbia.edu>


Holy mackerel!  Is this true?  Linnolt's record is pretty good. Can 
someone confirm?  And can everyone skip work, and work on this star 
tree-to-tree?

Waiting for BW Scl to erupt - it's been a long vigil.  If true, it's 
certainly the most important dwarf-nova eruption since WZ Sge in 1978. 
Despite the brevity of this message, it took me a long time to write it. 
  I made about 50 errors - from trembling fingers!

Just yesterday, our paper (Helena Uthas et al., MNRAS) on BW Scl at 
quiescence was finally accepted.  She'll forward it in a few days.  I 
don't remember including any "keep up a close watch" exhortation - but 
as many of you know, it's been on the prime WZ Sge watch-list for a long 
time... tied for #1 with GD 552 and MT Com.

joe




-------- Original Message --------
Subject: [vsnet-outburst 13345] Fwd: [AAVSO-DIS] BW SCL bright outburst 
  (v=9.6)!
Date: Fri, 21 Oct 2011 17:34:00 +0900
From: Hiroyuki Maehara <mira at cetus-net.org>
To: vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp
CC: vsnet-campaign-dn at ooruri.kusastro.kyoto-u.ac.jp, 
vsnet-outburst at ooruri.kusastro.kyoto-u.ac.jp

  According to M. Linnolt (via Aavso-discussion list), BW Scl is undergoing
a bright outburst. The orbital period of this object is 78.2 min 
(Augusteijn,
T. & Wisotzki, L. A&A 324, 57-60, 1997). The object is likely a WZ Sge-type
dwarf nova. Time-resolved observations are encouraged.

----- Forwarded message from Michael Linnolt <linnolt at hawaii.edu> -----
Date: Thu, 20 Oct 2011 21:54:26 -1000
From: Michael Linnolt <linnolt at hawaii.edu>
To: aavso-discussion at aavso.org
Subject: [AAVSO-DIS] BW SCL bright outburst (v=9.6)!
X-Mailer: Sun Java(tm) System Messenger Express 6.3-11.01 (built Feb 12 
2010;
	32bit)

Just observed this star at historical(?) brightness. V=9.6 !
Mike LMK


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From jop at astro.columbia.edu  Fri Oct 21 08:15:39 2011
From: jop at astro.columbia.edu (Joe Patterson)
Date: Fri, 21 Oct 2011 08:15:39 -0400
Subject: (cba:news) Fwd: Re:  BW SCL bright outburst  (v=9.6)!
Message-ID: <4EA1626B.7010201@astro.columbia.edu>

OK - thanks Matt. Ye australites, time to call in sick!

joe

Watch for saturation.  If you have a V or g filter, use it - it'll help 
with saturation issues, subdue or eliminate differential extinction, and 
put the data on a known standard magnitude system.



-------- Original Message --------
Subject: Re: (cba:news) BW SCL bright outburst  (v=9.6)!
Date: Fri, 21 Oct 2011 07:54:15 -0400 (EDT)
From: Matthew Templeton <matthewt at aavso.org>
To: Joe Patterson <jop at astro.columbia.edu>
CC: arne at aavso.org

Joe,

It was confirmed by Alan Plummer.

We've got a Special Notice in the bullpen, but we need to get a sequence
ready first.  Working on it now.

	Matt






From jop at astro.columbia.edu  Sun Oct 23 08:11:00 2011
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sun, 23 Oct 2011 08:11:00 -0400
Subject: (cba:news) (cba:chat) BW Scl colour index
In-Reply-To: <CA+1kM-iM+AVGcwmRafTjV5nD4_x0O-XGqv-rPnt8ZYnZgUjh-g@mail.gmail.com>
References: <9927B9619C7144219BD17BE1EBC491AC@Astronomy>	<3D0DA86DAA6F430CBC16CD588EEDECE5@obelix>
	<CA+1kM-iM+AVGcwmRafTjV5nD4_x0O-XGqv-rPnt8ZYnZgUjh-g@mail.gmail.com>
Message-ID: <4EA40454.3060704@astro.columbia.edu>

Hi BW Scl fans,

I'd suggest no B, as far as time series are concerned.  B is the least 
desirable (OK, U is worse) of all the filters, because there will be 
significant differential extinction: a slow bend as BW Scl reaches high 
airmass.  This will slightly degrade the period search; but more 
significantly, it will introduce low-frequency periodic signals, 
probably around 1.0 or 2.0 c/d.  V, R, and I are much better in this 
respect (extinction coefficients low and similar).

Also, some B filters are a little dark.  Check.

Because I consider time resolution to be very important, I'd advocate a 
straight V time series.  When dwarf novae are bright, the various 
commonly obtained time series (B,V,R,I) tend to be extremely similar, 
with no useful information (usually) obtained from the filters.  So you 
lose time resolution, with no real benefit.  Very late in the outburst
(probably when V>13 for this star), a significant and still-unexplained 
red excess sometimes appears.  That would be great to study for BW Scl. 
  You could do it with VI time series... or possibly with a fairly 
extensive snapshot coverage.

But probably straight V is best for the next 2-3 weeks. Assuming this is 
a super, which now seems very likely.  When it gets faint, the 
time-series (rather than snapshot) choice will probably be *unfiltered*. 
  Probably.

Finally, can anyone take *very fast* time series?  Many dwarf novae in 
outburst show periodic signals ("dwarf nova oscillations", or DNOs) 
around 20 s or thereabouts.  This requires excellent time-keeping and a 
cycle-time not exceeding 7-8 s.  Don't knock yourself out to do this, 
though - remember the Tortoise and the Hare.

BTW since I'm advocating against B, B observations may end up being 
particularly valuable (because there might be a lot fewer of them).  I 
doubt it, but maybe!  I *really* doubt it for time series... but 
possibly for snapshots.


joe


On 10/23/2011 7:32 AM, Arne Henden wrote:
> Josch, you should be able to use the B filter on targets like this.  The red
> leak for your B filter is only important for stars with (B-Ic)>5; that is,
> very red stars; and for objects with huge Halpha emission, such as novae.
> For all other stars, it is fine.
> Arne
>
> On Sun, Oct 23, 2011 at 7:16 AM, Josch Hambsch<hambsch at telenet.be>  wrote:
>
>> Should we commence with BVI filters? So far I did V, I as the B has a
>> infrared leakage. But if the star is blue I could also add B filtered
>> images.
>>
>> Regards,
>>
>> Josch
>>
>> http://www.astronomie.be/hambsch
>> ----- Original Message -----
>> From: "Terry Bohlsen"<terry.bohlsen at bigpond.com>
>> To:<vss-members at googlegroups.com>;<cba-chat at cbastro.org>
>> Sent: Sunday, October 23, 2011 12:14 PM
>> Subject: (cba:chat) BW Scl colour index
>>
>>
>>> Dear All
>>> I took a short V time series last night before the weather made me stop.
>> I
>>> interspersed this with a few UBVRI images. The data is uploaded to the
>>> AAVSO.
>>> The star is very blue with a B-V = -0.20 and U-B= -0.40
>>>
>>> Cheers
>>>
>>> Terry Bohlsen
>>> Armidale NSW Australia
>>> ____________________________________________________________
>>> Center for Backyard Astrophysics (CBA) mailing lists
>>> https://cbastro.org/communications/mailing-lists/
>>
>> ____________________________________________________________
>> Center for Backyard Astrophysics (CBA) mailing lists
>> https://cbastro.org/communications/mailing-lists/
>>
> ____________________________________________________________
> Center for Backyard Astrophysics (CBA) mailing lists
> https://cbastro.org/communications/mailing-lists/
>



From jop at astro.columbia.edu  Mon Oct 24 07:45:53 2011
From: jop at astro.columbia.edu (Joe Patterson)
Date: Mon, 24 Oct 2011 07:45:53 -0400
Subject: (cba:news) fuel for borealites, mainly
Message-ID: <4EA54FF1.1070803@astro.columbia.edu>


Dear CBAers,

Nearly all northerners are excluded from the BW Scl excitement this 
month (and next).  But the nights are long and clear in many parts of 
the northern CBA world, so here are some juicy targets.

Two prime evening guys.  Now that BW Scl has erupted, I'm thinking again 
of GD 552 = Cep 1.  A very, very similar star, also with no eruptions in 
history.  Same quiescent brightness (16.6).  BW Scl is extra-tantalizing 
because it shows MANY periodic signals in quiescence (probably most due 
to WD pulsation).  But we haven't done a really good study of GD552 - 
let's do it now!  It's still in prime position, and should reward very 
long time-series.

Plus RX2133+51 = "Cyg".  We've had very good coverage the last two 
years, started by David Boyd, and fervently continued by Enrique, Tut, 
Tom, Bob Koff, Etienne Morelle, and Jim Jones.  I just finished the 
analysis, and behold, what strange beast is slouching towards Cygnus!
It's a fine DQ Her star, beautiful detection and 9.5 minute pulse 
timings, sideband pulses at w-W, all very nice.  Five year baseline now 
for Pdot studies.  There's an "orbital" signal too, and it's at 6.729(1) 
hours.  Uh-oh... the "known" Porb, from spectroscopy and the separation 
between the spin signals, is 7.17(2) hours.  The nature of the new 
signal is unknown, but it's emphatically present in 2010 and 2011, and 
there's a tentative indication that it maintains phase coherence during 
the two years (together, not just separately).  Coherence would make it 
a little harder to just mutter "negative superhump".  (Although, at this 
point, it *is* what I mutter.)

Unless memory fails me, it's the first superhump which has shown up at 
such long Porb.  We've definitely been biased in our searches towards 
stars which "should" show superhumps.  It's a lot harder to work on the 
long periods - but it may well be a good choice as next-world-to-explore.

Two morning stars I highly recommend are RX0636+35 (Aur) and RX0704+26 
(Gem), both fine DQ Her stars needing work for pulse maintenance.  They 
too have long Porbs, and that's food for thought.

Under good conditions, VY Scl is also food for thought.  It's now in a 
faint state (17).  Our several studies at maximum light were quite 
unproductive; but there's a pretty good chance that this star will 
finally cough up its secrets at quiescence - if the (mainly southern) 
humans can take care of their business.  Long time series needed, to 
cover the range of periods that might be expected.

joe





From jop at astro.columbia.edu  Mon Oct 24 15:50:53 2011
From: jop at astro.columbia.edu (Joe Patterson)
Date: Mon, 24 Oct 2011 15:50:53 -0400
Subject: (cba:news) CSS233313-155744: an eclipsing dwarf nova with a
 61.7-min orbital period
In-Reply-To: <a34ef9ea4883092ae79256c6038063cd.squirrel@webmail.astro.columbia.edu>
References: <a34ef9ea4883092ae79256c6038063cd.squirrel@webmail.astro.columbia.edu>
Message-ID: <4EA5C19D.2020609@astro.columbia.edu>



http://www.astronomerstelegram.org/?read=3705

Wow, there's another new delight in the sky - and in the same part, 
though this one has some decent northern visibility as well.  61 
minutes, eclipses, superhumps, 17.4 - it's got our name, and yours, 
written all over it!  We'll try to get spectra tonight from MDM - you 
guys nail the light curves.

joe