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IAUC 5366: 1991bc; 1991ay, 1991bb; 1991n

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                                                  Circular No. 5366
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 1991bc IN UGC 2691
     Robert H. McNaught, Anglo-Australian Observatory, reports his
discovery of a supernova (mag about 16) on a J plate taken by M.
Hartley with the U.K. Schmidt Telescope on Oct. 12.7 UT.  The supernova
appears in UGC 2691, in the arm connecting the two galaxies of
this interacting pair, but much closer to the brighter, northern
component.  SN 1991bc is located at R.A. = 3h18m12s.92, Decl. =
-1 13'33".0 (equinox 1950.0, uncertainty 0".3 in each coordinate);
offsets from the center of the northern galaxy are 5" east, 6"
south.  No star of this brightness appears in this position on J or
I survey films or on the Palomar Sky Survey.  A nearby star of mag
about 18 has end figures 14s.49, 2".7.  B. Leibundgut, B. Schmidt,
and S. Gordon, Center for Astrophysics, report that a spectrogram
(range 400-900 nm) obtained Oct. 15 with the Multiple Mirror Telescope
shows this to be a type-Ia supernova within a week of maximum.
The Si II line at 615 nm appears stronger than in SN 1991bb.

SUPERNOVAE 1991ay AND 1991bb
     Leibundgut, Schmidt, and Gordon report further spectroscopic
observations (range 400-900 nm) with the MMT.  Their observation on
Oct. 15.5 UT confirms the classification by Filippenko (IAUC 5365)
of SN 1991bb in UGC 2892 as a type-Ia object; the spectrum indicates
that the supernova is near maximum.  Their observation of SN 1991ay
(IAUC 5352, 5356) on Oct. 13.2 UT shows this to be a type-Ia supernova
at about 1 month past its maximum; narrow emission lines from
the underlying galaxy indicate a redshift of 0.051.

     On Oct. 10 D. Rabinowitz, using the Spacewatch telescope at
Kitt Peak, detected a very diffuse band of light, some 1'-2' wide
and 2 deg long, extending beyond the field-of-view of the scan.  J.
Scotti confirmed the band with the same telescope the following
night and noted that the band could be traced to the head of P/Faye,
i.e., for > 10 deg; the band had a uniform width of about 2'.  The
earth crossed the plane of the comet's orbit on Oct. 13.3 ET.

1991 October 15                (5366)             Daniel W. E. Green

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