Central Bureau for Astronomical Telegrams

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IAUC 8892: COMET 17P/HOLMES; C/2007 N4-N8, C/2007 O3-O4, C/2007 Q4-Q7

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IAUC number 

                                                  Circular No. 8892
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)


COMET 17P/HOLMES
     B. Yang and D. Jewitt, University of Hawaii, report near-
infrared (0.8- to 4.2-micron) spectra of comet 17P taken with the
3.0-m NASA Infrared Telescope Facility by S. J. Bus on Oct. 27 and
28 UT.  Two broad absorption bands were found centered at 2.02
microns (the depth being 10 percent of the continuum) and 3.03
microns (30-percent deep), respectively, in the reflectance spectra
of 17P.  These features, which appeared on both nights, are
consistent with abundant water ice grains in the central coma.  The
overall slope of the infrared reflectance spectrum of this comet is
blue, with a normalized reflectance gradient near -2.3 percent per
100 nm.


COMETS C/2007 N4-N8, C/2007 O3-O4, C/2007 Q4-Q7 (SOHO)
     Further to IAUC 8891, additional Kreutz-sungrazing comets have
been found on SOHO website images, their "discovery" observations
tabulated below.  All eleven objects were stellar in appearance in
C3 images.  C/2007 N4, of mag 5.5 in C3 images, was slightly
diffuse with no tail in C2 images.  C/2007 N5, C/2007 N7, C/2007 Q4,
C/2007 Q5, and C/2007 Q7 were of mag about 6 in C3 images; C2
images showed C/2007 N5 to be quite diffuse with a hint of faint
tail, and C/2007 N7 to be slightly diffuse with a very faint short
tail.  C/2007 N6, C/2007 N8, and C/2007 O4 were faint (mag about 7)
in C3 images; however, C/2007 N6 appeared diffuse with no tail in
C2 images.  C/2007 O3 was tiny and very faint (mag 7.5).  C/2007 Q6
was very small and of mag about 6.5.  C/2007 Q7 was possibly
slightly elongated.

 Comet        2007 UT      R.A.(2000)Decl.   Inst.  F    MPEC
 C/2007 N4    July  3.613   6 37.2  +19 41   C3/2   HS   2007-U23
 C/2007 N5          7.904   6 52.8  +19 38   C3/2   BZ   2007-U23
 C/2007 N6         11.638   7 09.2  +20 06   C3/2   BZ   2007-U23
 C/2007 N7         13.179   7 11.2  +18 40   C3/2   KB   2007-U24
 C/2007 N8         13.346   7 14.6  +19 35   C3     BZ   2007-U24
 C/2007 O3         18.529   7 35.4  +19 43   C3     HS   2007-U24
 C/2007 O4         27.221   8 05.9  +17 05   C3     BZ   2007-U24
 C/2007 Q4    Aug. 17.238   9 22.4  +12 01   C3     SY   2007-U34
 C/2007 Q5         17.263   9 22.8  +12 22   C3     AK   2007-U34
 C/2007 Q6         17.529   9 28.1  +12 18   C3     HS   2007-U34
 C/2007 Q7         25.096   9 50.2  + 9 37   C3     HS   2007-U34

                      (C) Copyright 2007 CBAT
2007 November 7                (8892)            Daniel W. E. Green

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