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IAUC 6641: 1997bz; C/1995 O1

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                                                 Circular No. 6641
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)

     The Mount Stromlo Abell Cluster Supernova Search Team (cf.
IAUC 6418, 6639) reports the discovery of an apparent supernova (V
about 17.5) on V and R CCD images taken on Apr. 27 by S. Chan on
the Mount Stromlo 1.27-m telescope (+ Macho Camera).  SN 1997bz is
located near Abell 1238 at R.A. = 11h22m25s.46, Decl. = +1 11'21".5
(equinox 2000.0).  No star was detected at this position on frames
taken on Apr. 11.  SN 1997bz is also visible on CCD images taken
with the Mount Stromlo 1.27-m telescope on Apr. 30.  A nearby star
has position end figures 22s.56, 13'24".8.
     S. Jha, P. Challis, P. Garnavich, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, write:  "Spectrograms were
obtained by P. Berlind at the 1.5-m Tillinghast reflector on Apr.
30.18 UT and by P. Challis at the Multiple Mirror Telescope on May
2.15.  The spectra are heavily contaminated by the host galaxy, but
they indicate that SN 1997bz is of type Ia, slightly more than one
week after maximum.  The redshift derived from H-alpha emission in
the host galaxy is 0.03, implying that it is in the foreground of
the cluster (which is at redshift 0.072)."

     R. Meier, University of Hawaii (UH); H. Matthews, Joint
Astronomy Centre, Hilo, and National Research Council of Canada; T.
Owen and D. Jewitt, UH; M. Senay, University of Massachusetts; and
N. Biver, D. Gautier, D. Bockelee-Morvan, and J. Crovisier,
Observatoire de Paris, Meudon, report the detection of DCN in comet
C/1995 O1 with the James Clerk Maxwell Telescope at Mauna Kea on
Apr. 27.9 UT:  "The 10-sigma detection of the DCN 5-4 transition at
362.046 GHz was taken together with a quasi-simultaneous
measurement of the HCN 4-3 line.  Prior observations of HCN and
H_13CN 4-3 lines will allow an accurate, essentially model-
independent determination of the D/H ratio in cometary HCN.  Our
preliminary analysis leads to an approximate DCN/HCN ratio on the
order of 10E-3.  At the time of the observations, the comet was
passing in front of the Taurus dark clouds, and we have been
careful to exclude the possibility of contamination by background
sources.  The detection of DCN is the first detection of cometary
deuterium in a molecule other than water.  The availability of a
D/H ratio in both water (IAUC 6615) and a carbon-nitrogen-bearing
molecule may provide fundamental information on the origin and
evolution of comets."

                      (C) Copyright 1997 CBAT
1997 May 5                     (6641)            Daniel W. E. Green

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