[IAUC] IAUC 9175: 2010 V1; 103P [25139-2011/04-R1]

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                                                  Circular No. 9175
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
New postal address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBATIAU en EPS.HARVARD.EDU           ISSN 0081-0304
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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.
3.85.

     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     "


COMET 103P/HARTLEY
     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