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IAUC 6970: 1998cx; 1998cu; CH Cyg

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IAUC number 

                                                 Circular No. 6970
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


SUPERNOVA 1998cx IN NGC 6209
     A. Wassilieff, Palmerston North, New Zealand, reports his
discovery of an apparent supernova (mag about 17.8) on July 4.412
UT with a 0.36-m f/4.3 reflector (+ unfiltered SBIG ST-7 CCD).  G.
Nankivell, Wainuiomata, Lower Hutt, N.Z., provides the following
measurement for the position of SN 1998cx from a July 4 image by
Wassilieff:  R.A. = 16h54m55s.31, Decl. = -72o35'24".0 (equinox
2000.0), which is 10".9 west and 12".1 south of the nucleus of NGC
6209.  Further rough magnitudes from Wassilieff:  July 5, 17.8; 16,
18.3.  SN 1998cx does not show on a CCD image taken on 1993 Aug.
18, nor is it evident on a second-generation Digital Sky Survey
image.


SUPERNOVA 1998cu IN IC 1525
     S. Jha, P. Garnavich, P. Challis, and R. Kirshner, Center for
Astrophysics, report that a spectrum of SN 1998cu (cf. IAUC 6958)
taken by P. Berlind at the F. L. Whipple Observatory 1.5-m
telescope (+ FAST spectrograph) on July 15.4 UT exhibits a
prominent P-Cyg H-alpha feature, along with H-beta and Fe II
absorption, indicating that the supernova is of type II after
maximum light.  The photospheric expansion velocity measured from
the H-alpha profile is 5200 km/s, based on the NASA/IPAC
Extragalactic Database recession velocity for IC 1525 of 5022 km/s.


CH CYGNI
     M. Karovska, Harvard-Smithsonian Center for Astrophysics; C.
Carilli, National Radio Astronomy Observatory; and J. Mattei,
American Association of Variable Star Observers, report that they
have been monitoring the radio brightness changes of the symbiotic
system CH Cyg at 8, 15 and 22 GHz since Oct. 1996, following an
extreme fading of the visual brightness, to mag about 10.4, a few
months earlier (IAUC 6426):  "The radio brightness remained
relatively constant at about 6-8 mJy at all frequencies until Apr.-
May 1997, when we detected a sudden flux increase by about 50
percent at several frequencies; the visual magnitude was then about
9.4.  In addition to the flux measurements, we obtained high-
angular-resolution maps of CH Cyg at several frequencies showing
that the source is resolved.  Recent radio maps, obtained from
observations carried out during May-June 1998, show a significant
north-south elongation (of about 0".3), possibly indicating a jet
formation."

                      (C) Copyright 1998 CBAT
1998 July 16                   (6970)            Daniel W. E. Green

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