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IAUC 5282: 1991ae; 1991af; N Her 1991

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                                                  Circular No. 5282
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 1991ae IN MCG +11-19-018
     J. Mueller reports her discovery of a supernova 2" west and 8"
north of the nucleus of the galaxy MCG +11-19-018 (R.A. = 15 48.4,
Decl. = +68 15, equinox 1950.0).  The object was at B approx. 18 on a
plate taken on May 17 by C. Brewer, J. D. Mendenhall and herself with
the 1.2-m Oschin Telescope in the course of the Second Palomar Sky
Survey.  A spectrum obtained by W. Sargent and M. Strauss with the 5-m
Hale Telescope (+ double spectrograph) on June 6 shows strong H Alpha
and H Beta emission and He I 587.6-nm emission, indicating a peculiar
type II supernova; the object was then at mag approx. 17.

     J. Mueller also reports her discovery, from a similar plate taken
on May 19, of a supernova in an anonymous galaxy at R.A. = 17 25.1,
Decl. = +29 31 (equinox 1950.0).  The SN is 6".7 east and 3".3 south
of the center of the galaxy and had B approx. 18.5 mag.  A June 6
spectrum obtained as above indicates that this is a type II supernova.

     R. R. Joyce, Kitt Peak National Observatory, communicates:
"An infrared spectrum (range 1.4-3.9 microns, resolving power approx.
250) obtained on May 30.4 UT with the Cryogenic Spectrometer on the
KPNO 2.1-m telescope shows a continuum rising steeply with wavelength,
peaking at about 3.6 microns (in F-lambda units), roughly equivalent
to a blackbody of 800 K.  No emission features attributable to H or He
were detected, although three emission lines were detected in the H
and K bands, at 1.433, 1.740 and 1.966 microns.  There is a suggestion
of another emission line at the long limit of the K band, at
approximately 2.48 microns.  No lines above 15 percent of the
continuum were detected in the observed portion of the L band.  A
confirming spectrum of the 1.740-micron feature at 17-nm resolution
shows no substructure and a FWHM of approximately 3000 km/s.  A
tentative identification with [Si X] (1.430 microns), [Si VI] (1.960
microns) and [Si VII] (2.481 microns) suggests the onset of a coronal-
line phase as seen in V1500 Cyg.  Further spectroscopic monitoring is
clearly warranted."
     Visual magnitude estimates: May 22.08 UT, 14.7 (M. Verdenet,
Bourbon-Lancy, France); June 5.92, 13.9 (S. Korth, Dusseldorf, Germany).

1991 June 6                    (5282)              Brian G. Marsden

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