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IAUC 6057: 1994W; UZ Boo; 1994o

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                                                  Circular No. 6057
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505

     R. J. Cumming and P. Lundqvist, Stockholm Observatory; and W.
P. S. Meikle, Imperial College, London, report:  "A spectrogram
(range 428-800 nm, resolution 0.12 nm) of SN 1994W was taken with
the 4.2-m William Herschel Telescope (+ ISIS) at La Palma by M.
Breare and M. Azzaro on Aug. 13.9 UT.  The H-alpha profile shows
the same features as described on IAUC 6046 and is unchanged since
a high-resolution (0.03-nm) Isaac Newton Telescope spectrogram was
taken by E. J. Zuiderwijk on July 31.  In addition to the features
reported on IAUC 6046, we identify broad (FWHM 2000 km/s) emission
in He I at 447.1 and 706.5 nm, and narrow P-Cyg lines with absorption
minima at about -500 km/s (relative to the velocity of H II
emission from the galaxy near the supernova) in Mg II (448.1 nm),
He I (587.6 and 667.8 nm), Si II (634.7 and 637.1 nm), and O I
(777.3 nm).  An additional broad (FWHM 1500 km/s) emission feature
at 792 nm may be due to a blend of Mg II (789.6 and 787.7 nm).  The
constancy of the H I profiles and the presence of narrow P-Cyg
absorption suggest that the supernova is exciting a massive, dense
circumstellar shell, rather than a radiatively accelerated stellar
wind.  We expect the fastest supernova ejecta to reach this shell
soon, causing the dramatic disappearance of the narrow absorptions
as in SN 1984E (cf. IAUC 6048), broadening of the Balmer lines, and
perhaps x-ray and radio emission.  Continued observations at all
wavelengths are encouraged."

     Further visual magnitude estimates (cf. IAUC 6056): Aug. 16.84
UT, [14.3 (L. Szentasko, Veresegyhaz, Hungary); 17.490, 12.9 (Y.
Takenaka, Kyoto, Japan); 17.849, 12.0 (J. Pietz, Erftstadts, Germany);
18.188, 11.6 (R. Royer, Lakewood, CA); 18.477, 11.7 (T. Kato, Ouda
Station, Japan; CCD + V filter); 18.819, 12.1 (Szentasko); 18.869,
12.0 (P. Schmeer, Bischmisheim, Germany).

     Total visual magnitude estimates:  Aug. 14.42 UT, 9.4 (D.
Machholz, Colfax, CA, 0.25-m reflector); 16.080, 9.7 (K. Hornoch,
Lelekovice, Czech Republic, 0.13-m reflector); 16.23, 10.5 (C. E.
Spratt, Victoria, BC, 0.20-m reflector); 17.23, 10.3 (Spratt).

1994 August 19                 (6057)            Daniel W. E. Green

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