Re: [Fwd: CBET 2050: 20091126 : POSSIBLE NOVA IN ERIDANUS]

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Thu, 26 Nov 2009 04:22:21 -0500 · jop_at_astro.columbia.edu

Thanks, Gordon.  Now let's see if there's fast variability (anything, 
even flickering) in this star.  Novae when bright don't have it, and 
dwarf novae do - sometimes just a little, but this is really a pretty 
good discriminant, second only to a spectrum (which would be decisive).

The smart money now says this has a good chance of being a very nearby 
dwarf nova, like GW Lib, WZ Sge, etc.  At 8th magnitude, whew.  Find 
yourself a comp star and fire away - with a V filter, if you have one.
The star mentioned by Tom Krajci, GSC 5325-1544, 9' W of the target, is
probably a good choice (at V=10.25).  Filter it for calibration, and 
also to keep the counts down.

To avoid saturation you'll want short exposures - but only as short as 
you know your shutter/timing system can handle (for very short 
integration times, not all cameras will give an exactly repeatable 
exposure).  You can also consider stopping down the telescope aperture, 
or a little de-focusing.

It still might be some other kind of beast.  But if it's a WZ Sge star, 
it will greatly reward jumping early - often the orbital (as distinct 
from superhump) period manifests itself only in the first few days of 
outburst.

Hard to sleep tonight - and not because of the Thanksgiving parade in a 
few hours.

joe

Gordon Myers wrote:
> Joe,
> 
> Using Astrometrica I confirmed the nova location (I measured
> 4:47:54.18,-10:10:42.8). Astrometrica gave a V mag of 8.7. It does seem to
> be the star they refer to; my position measurement is even closer to those
> of the USNO star referenced. 
> 
> Gordon
> 
> -----Original Message-----
> From: cba-news-bounces@cbastro.org [mailto:cba-news-bounces@cbastro.org] On
> Behalf Of Joe Patterson
> Sent: Wednesday, November 25, 2009 9:12 PM
> To: cba-news@cbastro.org
> Subject: (cba:news) [Fwd: CBET 2050: 20091126 : POSSIBLE NOVA IN ERIDANUS]
> 
> Dear CBAers,
> 
> With a galactic latitude of 31 degrees and a possible range of 8 mag, 
> this could be an awfully interesting object.  It could be a very nearby 
> dwarf nova, or a really distant nova.  Or maybe something else... but 
> it's very much worth a looksee to figure out if the new object really is 
> that 15th mag star.  If it is, then I highly recommend a photometric 
> run!  And if not, well, it's still worth some study.
> 
> joe
> 
> -------- Original Message --------
> Subject: CBET 2050: 20091126 : POSSIBLE NOVA IN ERIDANUS
> Date: Wed, 25 Nov 2009 20:52:31 -0500
> From: IAUC mailing list <quai@cfa.harvard.edu>
> To: iauc@libraries.cul.columbia.edu
> 
>                                                    Electronic Telegram 
> No. 2050
> Central Bureau for Astronomical Telegrams
> INTERNATIONAL ASTRONOMICAL UNION
> M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
> IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
> CBAT@CFA.HARVARD.EDU (science)
> URL http://www.cfa.harvard.edu/iau/cbat.html
> 
> 
> POSSIBLE NOVA IN ERIDANUS
>       Hitoshi Yamaoka, Kyushu University, reports the discovery by K. 
> Itagaki
> (Yamagata, Japan) of a possible nova (mag 8.1) caught on Nov. 25.536 UT with
> his 0.21-m patrol system.  A confirming image taken by Itagaki on Nov. 
> 25.545
> with a 0.60-m reflector shows the object at R.A. = 4h47m54s.21, Decl. =
> -10d10'43".1 (equinox 2000.0).  Itagaki notes that there is a faint (mag 
> about
> 15) object near this position on his archival patrol images.  Yamaoka 
> suggests
> that it might be the brightening of a 15th-mag blue star that is 
> contained in
> many catalogues (USNO-B1.0 position end figures 54s.19, 42".9), noting that
> the amplitude of seven magnitudes is rather large for a dwarf nova, but
> somewhat small for a rapid classical nova.  Yamaoka adds that the ASAS-3
> system (Pojmanski 2002, Acta. Astron. 52, 397) also detected this object at
> the following V magnitudes:  Nov. 10.236 UT, [14.0:; 19.241, 7.34; 22.179,
> 7.98; 24.269, 8.12.
> 
> 
> NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
>        superseded by text appearing later in the printed IAU Circulars.
> 
>                           (C) Copyright 2009 CBAT
> 2009 November 26                 (CBET 2050)              Daniel W. E. Green
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> 