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IAUC 8550: 2005co, 2005cp; 9P

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                                                  Circular No. 8550
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/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

SUPERNOVAE 2005co AND 2005cp
     Further to IAUC 8544, E. Lee, N. J. Ponticello, and W. Li
report the LOSS discovery of two apparent supernovae on unfiltered
KAIT images:

SN      2005 UT      R.A.  (2000.0)  Decl.    Mag.     Offset
2005co  June 20.48  23 30 53.58  - 2 56 18.4  17.3   1".1 E, 16".0 S
2005cp  June 21.49  23 59 30.88  +18 12 09.6  17.4   5".8 E, 2".2 S

Additional approximate magnitudes from KAIT images:  SN 2005co in
IC 1496, 2004 Dec. 12.16 UT, [19.5; 2005 June 21.47, 17.4.
SN 2005cp in UGC 12886, Jan. 6.16, [19.5; June 22.47, 17.3.

     F. Bensch, Radioastronomisches Institut, Universitaet Bonn,
and Harvard-Smithsonian Center for Astrophysics (CfA); and G. J.
Melnick and B. M. Patten, CfA, write:  "Starting on June 5, daily
monitoring of the ortho water 1(10)-1(01) rotational line emission
at 556.936 GHz from comet 9P (the target of the Deep Impact mission)
has been made with the Submillimeter Wave Astronomy Satellite (SWAS).
During the period June 5.29-15.67 UT, the average integrated line
intensity detected within the 3'.3 x 4'.5 elliptical beam of the
SWAS telescope was 0.32 +/- 0.02 K km/s (main beam brightness).
The total water-production rate, Q(H_2O), is derived assuming an
H_2O ortho-para ratio of 3 and using the model by Bensch and Bergin
(2004, Ap.J. 615, 531), which is based on a spherical outflow
(Haser density profile) and the Monte Carlo radiative transfer code
by Hogerheijde and van der Tak (2000, A.Ap. 362, 697).  We obtain
Q(H_2O) = (1.1 +/- 0.1) x 10**28 s**-1 for the SWAS observations
made between June 5.29 and 15.67, assuming an electron abundance
similar to those derived by in-situ measurements in the coma of
1P/Halley.  However, the electron density in the cometary coma is
uncertain, and a 21-percent-greater water-production rate is
obtained for an electron abundance reduced by a factor of 0.2
(water-electron collisions significantly contribute to the
excitation of the water rotational line, in addition to water-water
collisions and infrared fluorescence).  Previous studies of the
556.936-GHz transition toward several other comets by SWAS and by
the (sub)millimeter-wavelength satellite Odin have indicated that
the electron density in cometary comae might be smaller by a factor
of about 0.2 (N. Biver, private communication, based on data from
Lecacheux et al. 2003, A.Ap. 402, L55, and Bensch et al. 2004,
Ap.J. 209, 1164)."

                      (C) Copyright 2005 CBAT
2005 June 22                   (8550)            Daniel W. E. Green

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