24 August 2010
IAU Circular No.9163
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.
2010 August 24 (9163) Daniel W. E. Green