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IAUC 5227: 1991N; N Her 1991; 1989t

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                                                  Circular No. 5227
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

     S. Perlmutter, C. Pennypacker, S. Carlson, N. Hamilton, H.
Marvin, R. Muller, M. Tetreault, and C. Smith communicate:  "The
Berkeley Automated Supernova Search reports the discovery of a
supernova of mv about 15 located 5" east and 7" south of the core of
galaxy NGC 3310 (R.A. = 10h35m.7, Decl. = +53 46', equinox 1950.0)
in two separate images taken on Mar. 29.4 UT.  The discovery was
confirmed on an image taken on Mar. 30.2, when the supernova was
about the same brightness.  The most recent previous image was taken
on Feb. 20.4 and showed no supernova to limit of mag 17.5 (95-
percent confidence level)."

     R. M. Wagner, R. Bertram, and B. Ali, Ohio State University;
and S. G. Starrfield, Arizona State University, report:  "Optical
spectra were obtained on Mar. 29.5 UT with the Perkins 1.8-m
telescope and CCD spectrograph (resolution 1 nm, range 335-980 nm) at
Lowell Observatory.  In addition to the features reported on IAUC
5223, broad emissions are visible at 447.1, 587.6, and 706.5 nm (He
I); 566.7 and 568.0 nm (N II); 597.8, 634.7, and 637.1 nm (Si II);
744.0, 820, and 870 nm (N I); 777.4 and 844.6 nm (O I); 787.7 and
789.6 nm (Mg II); and 911 (C I).  The FWHM width of H-alpha emission
was about 4500 km/s.  This spectrum is strikingly similar to that of
Nova V1500 Cyg obtained on 1975 Sept. 6-7 and shown by Tomkin et al.
(1976, A.Ap. 48, 319).  The appearance of He I lines after maximum
light in Nova Her 1991 (IAUC 5224) also coincides with the same
development observed in V1500 Cyg.  The large ejection velocities, the
rapid decline in optical light, the correspondence of optical
spectroscopic features, and the red color of the progenitor all suggest
that this is another case of a nova outburst occurring on a strongly
magnetized white dwarf."

     Total visual magnitude estimates (cf. IAUC 5157):  Jan. 13.56
UT, 12.2 (C. S. Morris, Pine Mountain Club, CA, 0.26-m reflector);
19.55, 11.9 (Morris); 24.53, 12.7 (A. Hale, Las Cruces, NM, 0.41-m
reflector); Feb. 17.53, 12.6 (Hale); Mar. 17.51, 12.7 (Hale).

1991 March 30                  (5227)             Daniel W. E. Green

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