Electronic Telegram No. 474
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT@CFA.HARVARD.EDU (science)
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COMET 73P/SCHWASSMANN-WACHMANN
     S. N. Milam, A. J. Apponi, L. M. Ziurys, and S. Wyckoff, Arizona
Radio Observatory and Steward Observatory, report that observations of
the J=1-0 transition of HCN at 88.6 GHz were conducted towards component
'C' of comet 73P on Apr. 11.36 UT with the Arizona Radio Observatory
12-m telescope on Kitt Peak.  Two out of three hyperfine components were
detected with intensities of 0.035 +/- 0.005 K for the F=2-1 transition
and 0.024 +/- 0.006 K for the F=1-1 line, with corresponding line widths
of 1.0 +/- 0.2 and 0.7 +/- 0.2 km/s, respectively.   These measurements
indicate a total column density of about 3.4 x 10^{11} cm^{-2} for HCN
in the 'C' source of 73P.  A production rate of Q(HCN) about 4.8 x
10^{23} s^{-1} was calculated using a Monte Carlo model, assuming that
this molecule is a parent species arising from the nucleus.  This
transition of HCN appears at the cometocentric velocity derived from
the JPL Horizons ephemeris.


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                         (C) Copyright 2006 CBAT
2006 April 12                    (CBET 474)               Daniel W. E. Green