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IAUC 9175: 2010 V1; 103P

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                                                  Circular No. 9175
Central Bureau for Astronomical Telegrams
New postal address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBATIAU@EPS.HARVARD.EDU           ISSN 0081-0304
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network

COMET 2010 V1
     S. Nakano, Sumoto, Japan, reports the visual discovery of a
comet independently by Kaoru Ikeya (Mori-machi, Shuchi-gun,
Shizuoka-ken; 25-cm reflector at 39x; diffuse with some
condensation; coma diameter 1' on Nov. 2.831 UT and 2' on Nov.
3.812) and by Shigeki Murakami (Toukamachi, Niigata-ken; 46-cm
reflector at 78x; coma diameter 4' with a 2' tail in p.a. 90 deg on
Nov. 3.801; moving eastward at approximately 2'/hr).  Nakano also
forwards astrometry obtained by Koichi Itagaki (Teppo-cho, Yamagata,
60-cm f/5.7 reflector + unfiltered CCD camera), who notes that comet
to be diffuse with strong central condensation but no tail on Nov.

     2010 UT             R.A. (2000) Decl.        Mag.   Observer
     Nov.  2.831     12 32.7       - 1 38         8.5   Ikeya
           3.801     12 35.1       - 2 01         9     Murakami
           3.812     12 35.0       - 2 01         8.0   Ikeya
           3.84701   12 35 04.22   - 2 02 12.5   10.5   Itagaki
           3.85035   12 35 04.71   - 2 02 17.2   10.7     "

     M. Knight and D. Schleicher, Lowell Observatory, report
narrowband imaging of comet 103P using the 0.8-m and Hall 1.1-m
telescopes at Lowell Observatory.  Further to Knight et al. (IAUC
9163), the CN gas feature was centered at p.a. about 355 deg on
Aug. 13-17; near 350 deg on Sept. 9-13 and on Oct. 16, 17, and 19;
and at about 5 deg during Oct. 31-Nov. 3.  This jet often appears
as a side-on corkscrew in recent images, but it is sometimes less
curved, possibly due to either the effects of a small complex
component to the fundamental rotation and/or an additional fainter
and overlapping jet located closer to the pole.  Numerical modeling
of these position angles and the sense of rotation yields a
rotation axis having an obliquity of about 15 deg in the comet's
orbital frame, corresponding to R.A. = 310 deg, Decl. = +80 deg,
assuming principal axis rotation.  Preliminary modeling suggests
that the CN jet originates at a latitude of +50 deg to +60 deg.  An
additional, fainter CN feature was seen towards the southeast (mid-
Oct.) and east (Oct. 31-Nov. 3).  For this pole solution, the
comet's maximum sub-earth latitude is attained in early October,
resulting in an overlap of the two CN features towards the east, as
was observed in the Oct. 12-14 images and possibly explaining the
morphology described by Samarasinha et al. (CBET 2512).  With this
pole solution, the sub-earth latitude should be near the comet's
equator at the time of the EPOXI spacecraft encounter, yielding the
side-on corkscrews.

                      (C) Copyright 2010 CBAT
2010 November 3                (9175)            Daniel W. E. Green

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