THE ASTRONOMER Electronic Circular No 721       1993 Mar 30 18.32UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England. Telephone/FAX(0256)471074 Int:+44256471074
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SUPERNOVA 1993J IN NGC 3031
Further to the initial report relayed by Mark Kidger via STARLINK/
SPAN and which we forwarded to you earlier today, the object has
now been confirmed as detailed below. Mark has also faxed a chart
showing the location of the object and we will endeavour to produce
an e-mail chart as soon as possible. For those with the Thompson/
Bryan charts, the object lies north-east of star '140' which is
double-underlined and south of the nucleus-Editor.

J. Ripero, Madrid, Spain, reports that F. Garcia, Lugo, Spain,
discovered a possible supernova on Mar. 28 as much as 5' southwest
of the nucleus of NGC 3031 = M81.  The object was also recorded in
an ST-4 CCD image obtained by D. Rodriguez as some 30" northeast of
a mag 14 foreground star. Magnitude estimates: Mar. 26.9 UT, [14.0
(Garcia and P. Pujol); 28.86, 12.0 (Garcia, visual), 29.1, 11.8
(Rodriguez, CCD unfiltered); 29.88, 11.3 (Pujol); 29.88, 11.0
(Rodriguez).
A. V. Filippenko, University of California at Berkeley, reports:
"A CCD image of M81 obtained on Mar. 30.1 UT by R. R. Treffers
and Y. Paik (also of Berkeley) with the 0.8-m reflector at
Leuschner Observatory confirms the presence of a new stellar object
roughly 45" west and 160" south of the nucleus. The visual
magnitude is approximately 11. Inspection of CCD spectra (range
356-731 nm) obtained on Mar. 30.3 by M. Davis and D. Schlegel (also
of Berkeley) with the Lick 3-m Shane reflector reveals that the
object is indeed a supernova.  The continuum is very blue and
remarkably featureless. The only clear absorption lines are narrow
Na I D and Ca II H + K, undoubtedly of interstellar origin.  It is
probable, but not yet certain, that the object is a type II
supernova observed only a few days after the explosion.  Note,
however, that the type Ia SN 1991T exhibited a relatively
featureless spectrum well before maximum brightness (Filippenko et
al. 1992, Ap.J. 384, L15).  Depending on its spectral type,
distance and extinction, SN 1993J may reach eighth magnitude during
the next two weeks.  Aside from SN 1987A in the LMC, it is
therefore the brightest supernova since SN 1972E in NGC 5253.
Further observations throughout the electromagnetic spectrum are
urged."
F. D. A. Hartwick, D. D. Balam, D. Zurek and R. M. Robb, Climenhaga
Observatory, University of Victoria, provide the following precise
position for the supernova, measured by Balam from a CCD image
obtained with the 0.5-m reflector on Mar. 30.25 UT:
     R.A. = 9h51m19s.27, Decl. = +69D15'25".7 (equinox 1950.0).
Photometry yields V = 10.2 +/- 0.1.
P. Garnavich and B. A. Hong, Dominion Astrophysical Observatory,
communicate: "Spectra (range 550-690 nm, resolution 0.6 nm) of the
supernova were taken with the DAO 1.8-m telescope on Mar. 30.25 UT.
The spectrum shows a strong, flat continuum with weak H alpha and
He I 587.5 nm) features, consistent with that of a type II
supernova."
IAUC 5731