(cba:news) New outbursting dwarf novae - battle stations
jop at astro.columbia.edu
Mon Jan 21 22:55:07 EST 2008
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
-------- 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
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)
DWARF NOVA IN CANIS MINORIS
H. Yamaoka, Kyushu University, reports that K. Itagaki (Yamagata,
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
apparently measured from an image obtained with a 0.30-m reflector).
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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