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IAUC 6120: 1994ai; 1993J; EX Hya

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                                                  Circular No. 6120
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444     TWX 710-320-6842 ASTROGRAM CAM

     A. Williams and R. Martin report their discovery at the Perth
Observatory of an apparent supernova located about 24" east and 4"
north of the center of NGC 908 (R.A. = 2h20m46s, Decl. = -21o27'.6,
equinox 1950.0).  The object was found on an image taken on Dec.
20.52 UT in the course of the Perth Astronomy Research Group's
automated supernova search.  Estimated unfiltered magnitudes:  Dec.
8, [19; 16, 17-18; 20.52, 16-17.
     S. Benetti, European Southern Observatory, reports that
inspection of a preliminarily-reduced CCD spectrum (range 400-800
nm, resolution 2.6 nm), obtained on Dec. 24.11 UT with Danish 1.54-
m telescope (+ DFOSC) at La Silla, confirms that SN 1994ai is a
supernova of type Ic around maximum.  Lines (with P-Cyg profile) of
Fe II, Na I D, Si II 635.5-nm, and O I 777.4-nm are superimposed on
a red continuum.  The expansion velocity deduced from the minimum
of the Na I D, Si II, and O I lines, corrected by the recession
velocity of 1700 km/s of the parent galaxy (measured from the Na I
D interstellar lines), is about 8000 km/s.

     H.-U. Zimmermann, B. Aschenbach, G. Hasinger, W. Pietsch, P.
Predehl, and J. Trumper, Max-Planck-Institut fur Extraterrestrische
Physik; W. Lewin, Massachusetts Institute of Technology; J. van
Paradijs and E. Magnier, University of Amsterdam; G. Fabbiano,
Center for Astrophysics; L. Lubin, Princeton University; and R.
Petre, Goddard Space Flight Center, report:  "SN 1993J was again
observed with ROSAT between Oct. 19 and 21; during a 20~000-s
observation with the HRI detector (which has no spectral
resolution), a mean rate of 0.0072 count/s was recorded.  Under the
assumption that the spectral shape in the ROSAT band (0.1-2.4 keV)
has not drastically changed since April 1994 (cf. IAUC 6014), the
soft-x-ray flux has remained roughly constant since then.  This may
indicate that the shock wave has now entered regions with higher
matter densities."

     A. Jones, Nelson, New Zealand, reports that this cataclysmic
variable is in outburst, as indicated by his visual magnitude
estimates:  Dec. 24.58 UT, 13:; 25.60, 9.6; 25.64, 9.4.

1994 December 26               (6120)            Daniel W. E. Green

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