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IAUC 5638: 1992bd; N Cyg 1992

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                                                  Circular No. 5638
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

SUPERNOVA 1992bd IN NGC 1097
     Chris Smith, Cerro Tololo Interamerican Observatory; and Lisa
Wells, Kitt Peak National Observatory, report their discovery of a
supernova located 1".5 east and 9" south of the nucleus of NGC 1097
(R.A. = 2h44m11s, Decl. = -30 29'.1, equinox 1950.0).  The object
was found in a 20-min I-band CCD exposure taken by Smith on Oct.
12.26 UT with the CTIO 0.9-m telescope; it is also apparent in B,
V, and R CCD images taken subsequently, and has a magnitude of V
about 15 and a color of B-V about +2.6.  Nothing is visible at this
location in published images of the nucleus of NGC 1097 (e.g.,
Rickard 1975, A.Ap. 40, 339).  Due to the highly reddened nature of
this object, infrared and radio observations may prove interesting.
     M. Della Valle and P. Bouchet, European Southern Observatory,
report:  "Inspection of a spectrogram (range 400-830 nm, resolution
about 1 nm) of SN 1992bd, obtained under poor meteorological conditions
on Oct. 17.1 UT with the New Technology Telescope (+ EMMI) at
La Silla, shows this object to be a type-II supernova.  The spectrum
is dominated by the emissions of H-alpha and Na I D, flanked
by deep P-Cyg profiles.  The expansion velocity, corresponding to
the difference between the rest wavelength in the galaxy's frame
and the minimum of the absorption, is about 7500 km/s.  Other
strong emission lines are observed at 489 (H-beta), 493, 543, 570,
and 615 nm."

     G. S. Rossano, R. J. Rudy, R. C. Puetter, and D. K. Lynch,
Space and Environment Technology Center, The Aerospace Corporation,
report:  "We observed this object on Oct. 6.3 and 8.3 UT with the
Lick Observatory 3-m Shane telescope (+ cooled scanning germanium
spectrometer with a 10" x 8" oval aperture).  Spectroscopic observations
(range 0.75-1.35 microns, resolution 300-550) indicate that
N Cyg 1992 has changed little in appearance since August, showing
strong lines of the Paschen series, and strong He I 1083.0-nm,
along with other lines of He I, He II, O I, [O II], [N I], [S II],
and [S III].  The strength of the O I lines has decreased, and an
unidentified feature at 1110 nm has increased markedly in strength.
A monochromatic magnitude of 8.9 at 1.25 microns was observed on
Aug. 8.3."
     Selected visual magnitude estimates:  Sept. 23.24 UT, 8.8 (R.
A. Keen, Golden, CO); 30.14, 9.4 (W. G. Dillon, Missouri City, TX);
Oct. 4.79, 9.1 (H. Dahle, Oslo, Norway); 9.01, 9.1 (B. H. Granslo,
Fjellhamar, Norway); 13.94, 9.4 (P. Schmeer, Bischmisheim, Germany).

1992 October 17                (5638)            Daniel W. E. Green

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