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IAUC 8391: C/2003 K4; 2004dj

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                                                  Circular No. 8391
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)

     M. L. Sitko, University of Cincinnati; R. W. Russell, D. K.
Lynch, and D. L. Kim, Aerospace Corporation; and R. B. Perry,
Langley Research Center, NASA, report on further infrared
spectrophotometry of comet C/2003 K4 (cf. IAUC 8361, 8378),
obtained on Aug. 5.3 and 6.3 UT using the Aerospace Corporation's
BASS spectrograph at the Infrared Telescope Facility 3-m reflector.
A smooth continuum was seen between 8 and 13 microns, with a
possible weak silicate emission band superimposed.  Underlying
blackbodies with temperatures of 250 +/- 5 K and 245 +/- 5 K were
fitted to the continuum fluxes at 8.4 and 12 microns on Aug. 5 and
6, respectively.  These grain temperatures are about 8-10 percent
higher than that of an equilibrium blackbody at the comet's
heliocentric distance.  Using the 10.2-10.7-microns region to
calculate a silicate feature-to-continuum ratio, this ratio was
1.09 +/- 0.03 on Aug. 5, and 1.03 +/- 0.03 on Aug. 6.  On Aug. 5, a
weak feature due to crystalline olivine may have been present at
11.2 microns.  Scattered solar radiation was evident at wavelengths
shorter than 4 microns.  The observed magnitudes determined between
10.2 and 10.7 microns, using the instrument's 3".4 aperture and 18"
nod, were 2.8 and 2.7 on Aug. 5 and 6, respectively (+/- 0.03 mag,
the errors being dominated by the presence of variable sky
transparency during the observations).

SUPERNOVA 2004dj IN NGC 2403
     A. V. Filippenko and W. Li, University of California, Berkeley;
P. Challis, Harvard-Smithsonian Center for Astrophysics; and S. D.
Van Dyk, Infrared Processing and Analysis Center, California
Institute of Technology, report:  "We have examined optical images
of SN 2004dj obtained on Aug. 17 UT with the Wide Field Camera of
the Advanced Camera for Surveys aboard the Hubble Space Telescope.
Although the supernova is very saturated in these images, it is
clearly located within the compact star cluster Sandage 96,
confirming the suggestion made on IAUC 8385 and justified in detail
by Maiz-Apellaniz et al. (http://xxx.lanl.gov/abs/astro-ph/?0408265).
The tentative identification of a different progenitor star made by
Li et al. (IAUC 8388) was based on the radio position reported on
IAUC 8379 by Stockdale et al., which is possibly affected by
inclusion of extended radio emission in the host galaxy (observed
in the VLA-D configuration at 8.46 GHz)."

                      (C) Copyright 2004 CBAT
2004 August 18                 (8391)            Daniel W. E. Green

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