(cba:news) [Fwd: CBET 2275: 20100508 : CATACLYSMIC VARIABLE IN PEGASUS]
jop at astro.columbia.edu
Sat May 8 16:19:33 EDT 2010
Here's a lot more info on this fascinating star. So far, the
magnitudes, spectrum, and proper motion are all highly consistent with
the WZ Sge class - indeed, a quite good match (so far) with the great WZ
itself. Drag the telescope into that morning chill, and watch those
beautiful light curves come rolling out of your cameras!
And let us know what you find! This message contains, among other
goodies, the exact positional information.
If you have a V filter, that would be a good choice. R is good, too.
The star is bright enough (and probably will remain so) to survive
filtering, plus the obvious advantages: standardization, better control
of extinction, etc. However, eventually we're going to have to all
convert to unfiltered (to get good signal-to-noise late in the
outburst)... and *some* unfiltered observation now will help make this
transition more tractable.
-------- Original Message --------
Subject: CBET 2275: 20100508 : CATACLYSMIC VARIABLE IN PEGASUS
Date: Sat, 8 May 2010 14:55:30 -0400 (EDT)
From: quai at cfa.harvard.edu
To: IAUC at libraries.cul.columbia.edu
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbat at iau.org; cbatiau at eps.harvard.edu
CATACLYSMIC VARIABLE IN PEGASUS
[Editor's note: the following text replaces that on CBET 2274]
S. Nakano, Sumoto, Japan, reports the independent discovery of the
outburst of this variable (cf. CBET 2273) by Shizuo Kaneko (Kami-Yashiki,
Kakegawa, Shizuoka-ken) at mag 9.0 on two 20-s exposures (limiting mag 12.4)
taken on May 7.787 UT with a Contax 80-mm f/2.0 camera lens (+ Canon Kiss
Digital X camera); nothing was visible at this position on a frame taken
by Kaneko on May 1.742 with the same instrumentation. From Kaneko's
discovery frame, Nakano measures mag 9.1 (limiting mag 13.2) and the
following position for the variable: R.A. = 21h38m07s.03, Decl. =
+26d20'03".0 (equinox 2000.0; probable error +/- 4"), adding that a faint
star of mag around 14 is visible at position end figures 11s.5, 01".
H. Yamaoka, Kyushu University, reports that the variable appears at
mag about 15 (near the limiting magnitude) on a CCD survey image taken
by K. Itagaki (Yamagata, Japan) on May 1.71 UT with a 0.21-m telescope,
which suggests that the star was then at a quiesient phase; Itagaki
provides position end figures 06s.66, 19'57".1 and mag about 8.8 from an
image taken on May 8.657 UT with his 0.60-m telescope, indicating that
the outbursting object is a southern component of a double star GSC
2197:866 (cf. CBET 2273).
A. Henden, AAVSO, notes that Palomar Sky Survey (POSS) plates show a
close pair of objects at the location of the outbursting variable: one is
essentially stationary, while the other has a relatively high proper motion.
On the POSS-I plates, the southwest component of the 3"-separated double is
obviously blue, while on the POSS-II plates, it has moved east-northeast by
about 3" and is now about 1" southeast of the stationary northeast
At this motion rate, it would be expected to lie an arcsec or two east
stationary component at this epoch. This rate of motion would imply
something intrinsically faint but relatively close; adding in the color
would imply a white dwarf -- suggesting that the moving object is the
outbursting object and that it is a cataclysmic variable with an amplitude
of about 6 magnitudes.
P. Camilleri, Sydney, Australia, obtained two unfiltered CCD images of
the variable remotely at the Tzec Maun Observatory in New Mexico using a
Takahashi Epsilon 0.18-m f/2.8 corrected Newtonian reflector (May 8.371 UT,
mag 9.3) and a 0.35-m Maksutov-Newtonian f/3.8 reflector (May 8.388, mag
yielding position end figures 06s.64 +/- 0s.02, 19'56".8 +/- 0".1.
Tabulated summary of the available data from CBET 2273 and above:
2010 UT R.A. (2000.0) Decl. Mag. Observer
May 1.71 15 : Itagaki
1.742 [13 : Kaneko (Nakano)
6.77 (21 38 06.6 +26 19 57) 10.8 Yi
7.76 8.4 Yi
7.787 21 38 07.03 +26 20 03.0 9.1 Kaneko (Nakano)
8.371 21 38 06.63 +26 19 56.7 9.3 Camilleri
8.388 21 38 06.66 +26 19 56.8 8.9 Camilleri
8.657 21 38 06.66 +26 19 57.1 8.8 Itagaki
M. L. Graham, H. Broekhoven-Fiene, A. H. Parker, S. Sadavoy, and A. J.
Maxwell, Department of Physics and Astronomy, University of Victoria; E. Y.
Hsiao, Lawrence Berkeley Laboratory; and D. D. Balam, Dominion Astrophysical
Observatory, National Research Council of Canada, report that a spectrum
(range 390-703 nm, resolution 0.3 nm) of this variable (cf. CBET 2273),
obtained on May 8.47 UT with the 1.82-m Plaskett Telescope of the National
Research Council of Canada, shows strong H-alpha and H-beta in emission
(HWFM 800 km/s), as well as He II (468.6 nm) and a broad emission feature
centered at 465 nm that is interpreted as the Bowen complex of N III, C III,
and C IV. All members of the Balmer series show shell-like profiles with
both red and blue absorption components.
A. Arai, Kyoto Sangyo University, reports that an optical spectrogram
(resolution 500) of the variable was obtained using the 1.3-m ARAKI
on May 8.66 UT under poor sky conditions. The spectrum shows a blue
continuum and a weak H-alpha emission line (EW about 0.4 nm), suggesting
that the object would be classified as a dwarf nova. No other significant
emission or absorption lines were seen in the low-S/N data.
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2010 CBAT
2010 May 8 (CBET 2275) Daniel W. E. Green
iauc mailing list
iauc at astro.columbia.edu
More information about the cba-public