(cba:news) New outbursting dwarf novae - battle stations

[Joe Patterson]

Dear CBAers,

Two new outbursting dwarf novae in the last 2 days - both with excellent 
prospects for being the short-period WZ Sge-type which have been so good 
to us... and both superbly placed in the sky for all hemispheres.

The first is the one attached, a dwarf nova in Canis Minor (0747+06), 
and a few minutes ago large-amplitude superhumps were first reported.
Fire away!  I believe mag 12.5 tonight.  I think Tom Krajci is setting 
up on it right now.

The second is OT084555.1+033930, also excellently placed, as you can see 
from the position.  Also about mag 13 I think.

And the third star which should share center stage to some extent is
OT111217.4-353829, a star which Greg Bolt covered thoroughly for the 
first few weeks of outburst.  It's still bright and quite possibly still 
superhumping.  Almost certainly an EXTREMELY INTERESTING star... and now
better placed for observing.

I'll forward a few messages which might be of interest in learning about 
these targets... although VERY LITTLE is known about 'em yet (this is 
the "discovery eruption" for each one of these stars).

These stars deserve first priority in our pantheon.  It's not that "all 
the children are above average"... they really are likely to be great 
winners!

joe

-------- Original Message --------
Subject: CBET 1216: 20080120 : DWARF NOVA IN CANIS MINORIS
Date: Sun, 20 Jan 2008 16:03:05 -0500 (EST)
From: IAUC mailing list <quai at cfa.harvard.edu>
To: iauc at libraries.cul.columbia.edu

                                                   Electronic Telegram 
No. 1216
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS at CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT at CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


DWARF NOVA IN CANIS MINORIS
      H. Yamaoka, Kyushu University, reports that K. Itagaki (Yamagata, 
Japan)
has discovered a variable star (mag 12.3) on unfiltered CCD images obtained
with a 0.21-m reflector on Jan. 19.546 UT, the "new" object located at R.A.
= 7h47m27s.64, Decl. = +6o50'50".0 (equinox 2000.0; photometry and 
astrometry
apparently measured from an image obtained with a 0.30-m reflector). 
Nothing
is visible at this position on Itagaki's image from 2007 Oct. 17 (limiting
mag 17.5), though a faint star of mag about 19.5 is within 1" of this
position in both the USNO-B1.0 and GSC 2.3.2 catalogues.  H. Naito and S.
Narusawa, Nishi-Harima Astronomical Observatory (NHAO), report (via Yamaoka)
that a low-resolution (R about 270) spectrum (range 410-670 nm), taken on
Jan. 19.63 UT with 2.0-m NAYUTA telescope at NHAO under hazy conditions,
shows a smooth, blue continuum with absorption lines of the Balmer series,
which indicates that the new variable is a dwarf nova in outburst; the
equivalent widths of H_beta and H_gamma are 0.6 and 0.7 nm.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
       superseded by text appearing later in the printed IAU Circulars.

                          (C) Copyright 2008 CBAT
2008 January 20                  (CBET 1216)              Daniel W. E. Green
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