[IAUC] IAUC 9163: P/2010 Q1; 103P [25139-2011/04-R1]

[quai en cfa.harvard.edu]

                                                  Circular No. 9163
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  D. W. E. Green, Room 209; Department of
 Earth and Planetary Sciences; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBAT en IAU.ORG; CBATIAU en EPS.HARVARD.EDU
URL http://www.cfa.harvard.edu/iau/cbat.html  ISSN 0081-0304


COMET P/2010 Q1 (SCOTTI)
     J. V. Scotti, University of Arizona, reports the recovery of
comet P/2000 Y3 (cf. IAUCs 7552, 7553) as an essentially stellar
object on images obtained on Aug. 19 and 20 with the 0.9-m
Spacewatch reflector at Kitt Peak (first observation tabulated
below).

     2010 UT             R.A. (2000) Decl.       Mag.   Observer
     Aug. 19.37705    1 57 22.03   +13 10 01.1   20.9   Scotti

The indicated correction to the prediction on MPC 65937 is Delta(T)
= -0.46 day.  The astrometry (including accidental observations
obtained by T. H. Bressi on 2009 Sept. 18 with the 1.8-m Spacewatch
reflector), linked orbital elements (epoch 2012 Feb. 3.0 TT, T =
2012 Jan. 20.3218 TT, e = 0.199930, q = 3.918196 AU, Peri. =
92.5913 deg, Node = 354.1592 deg, i = 2.2591 deg, equinox 2000.0, P
= 10.84 years), residuals, and an ephemeris appear on MPEC 2010-Q19.


COMET 103P/HARTLEY
     M. Knight, E. Schwieterman, and D. Schleicher, Lowell
Observatory, obtained and analyzed extensive CN narrowband images
of comet 103P on five consecutive nights (2010 Aug. 13-17) using
the Hall 1.1-m telescope at Lowell Observatory.  Following the
removal of median radial profiles, an oscillating CN gas feature is
seen centered near position angle 350 deg, consistent with a side-
on cork-screw jet morphology; no dust feature other than the tail
was visible in R-band images.  Intervals between 15 pairs of
matching CN images from various rotational cycles, coupled with the
spacing and the outward motion of the feature, imply a nucleus
rotation period of 16.6 +/- 0.5 hr, consistent with the result by
Meech et al. (2009, BAAS 41, 1029).  Preliminary modeling suggests
a moderate obliquity of the rotation axis and a mid-latitude source
location.
     Schleicher adds that he obtained six sets of narrowband
photometry of comet 103P on Aug. 11 and 12 (when r = 1.48-1.47 AU)
using the Hall 1.1-m telescope, resulting in the following averaged
production rates:  log Q(OH) = 27.04; equivalent log Q(water;
vectorial) = 27.09; log Q(NH) = 24.87; log Q(CN) = 24.48; log Q(C_2)
= 24.56; log Q(C_3) = 23.86; log af(rho)(526.0 nm) = 0.93 (cf. IAUC
7342).  There is possible evidence of rotational variability, with
values for CN and C_3 lower by 10 percent on Aug. 12 vs. Aug. 11,
while dust was lower by about 20 percent.  The implied very-low-
dust-to-gas ratio, based on af(rho) vs. Q(OH), matches Schleicher's
measurements from the 1991 and 1997 apparitions.

                      (C) Copyright 2010 CBAT
2010 August 24                 (9163)            Daniel W. E. Green