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IAUC 6421: 1996ah; C/1995 O1

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                                                  Circular No. 6421
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 (for emergency use only)

SUPERNOVA 1996ah IN NGC 5640
     J. Mueller reports her discovery of a supernova (mag about 18)
located 4".7 west and 3".3 south of the center of NGC 5640 (R.A. =
14h20m.8, Decl. = +80o06', equinox 2000.0).  Mueller found SN
1996ah on a IIIa-F plate taken by K. M. Rykoski and herself on June
6 with the 1.2-m Oschin Schmidt telescope in the course of the
second Palomar Sky Survey.
     P. Garnavich, P. Challis, A. Riess, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, report:  "A CCD image obtained
with the F. L. Whipple Observatory's 1.2-m telescope on June 17.3
UT confirms the presence of SN 1996ah, 5" west and 1" south of the
galaxy nucleus.  A spectrum taken with the Multiple Mirror
Telescope on June 19.3 shows that this is a type-Ia supernova
between two and three weeks past maximum."

     N. Biver, D. Bockelee-Morvan, P. Colom, J. Crovisier, E.
Gerard, and H. Rauer, Observatoire de Paris-Meudon; D. Despois,
Observatoire de Bordeaux; R. Moreno and G. Paubert, Institut de
Radio Astronomie Millimetrique (IRAM), Granada; and J. K. Davies
and W. R. F. Dent, Joint Astronomy Centre, Hilo, report the first
detections of CS and H2CO and observations of CO, HCN, CH3OH and
H2S lines in comet C/1995 O1 with the IRAM 30-m telescope performed
on June 14--17:  "We observed integrated main-beam brightness
temperatures of 0.18 +/- 0.03 (CO, 115 GHz); 0.69 +/- 0.014 (CO,
230 GHz); 0.76 +/- 0.02 (HCN, 89 GHz); 1.20 +/- 0.03 (H2S, 168 GHz);
0.085 +/- 0.011 (H2CO, 225 GHz); and 0.10 +/- 0.007 (CS, 147 GHz),
in units of K km sE-1.  The rotational temperatures observed for
CH3OH are 14 +/- 1 K from lines around 145 GHz and 26 +/- 5 K from
lines around 157 GHz.  The estimated production rates in units of
10E28 molecules/s are:  CO, 8; HCN, 0.07; CH3OH, 0.6; H2S, 0.5;
H2CO, 0.010 (assuming parent distribution); and CS, 0.014 (assuming
daughter distribution with parent scalelength of 8000 km).  At the
same period, the OH-production rate from 18-cm observations at the
Nancay radio telescope was 12.3 +/- 1.3 x 10E28 sE-1."
     Visual m1 estimates:  June 13.95 UT, 6.3 (K. Hornoch,
Lelekovice, Czech Republic, 10x80 binoculars); 15.00, 6.3 (R. J.
Bouma, Groningen, The Netherlands, 10x50 binoculars); 16.32, 6.3
(C. S. Morris, Lockwood Valley, CA, 10x50 binoculars); 19.00, 6.2
(R. Haver, Frasso Sabino, Italy, 15x80 binoculars).

                      (C) Copyright 1996 CBAT
1996 June 19                   (6421)            Daniel W. E. Green

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