Central Bureau for Astronomical Telegrams
IAUC 9272: (2340); (62412) 2000 SY_178
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Circular No. 9272
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@EPS.HARVARD.EDU ISSN 0081-0304
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network
(2340) HATHOR
J. D. Giorgini, Jet Propulsion Laboratory (JPL); E. S. Howell,
P. A. Taylor, J. E. Richardson, L. A. Ford, L. F. Zambrano-Marin,
and M. C. Nolan, Arecibo Observatory, National Astronomy and
Ionosphere Center; and M. Brozovic and L. A. M. Benner, JPL, report
that a strongly-detected (though small) non-gravitational
acceleration, consistent with Yarkovsky thermal re-radiation, has
been observed influencing the motion of minor planet (2340) Hathor.
Arecibo (2380-MHz, 12.6-cm) and Goldstone (8560-MHz, 3.5-cm)
round-trip delay measurements of (2340) Hathor on Oct. 20-22
detected offsets of 2498.6 (+/- 0.3) x 10**-6 seconds and 2499.2
(+/- 3.0) 10**-6 seconds relative to the ballistic trajectory
predicted from initial plane-of-sky angular measurements spanning
1976-2012 (JPL orbit solution no. 48, dated 2014 June 9; most
recent orbits for minor planets are posted at website URL
http://ssd.jpl.nasa.gov/dat/ELEMENTS.NUMBR). This 22-sigma delay
offset, along with a 4.6-sigma Doppler frequency shift offset
relative to the pre-radar prediction, are dynamically consistent
with a heliocentric transverse non-gravitational acceleration
(approximating Yarkovsky thermal acceleration over the time span)
of -6.1 +/- 0.3 x 10**-13 m/s**2, estimated in JPL orbit solution
no. 60 (from 2014 Oct. 24) using a combined astrometric dataset of
182 optical measurements (1976-2014) with four radar delay and
three Doppler measurements. Radar imaging with 15-m resolution
suggests a diameter of 210 +/- 30 m and a generally spheroidal
shape with little or only moderate elongation.
(62412) 2000 SY_178
S. S. Sheppard, Carnegie Institution for Science, Washington;
and C. A. Trujillo, Gemini Observatory, report the detection of a
faint tail to the main-belt minor planet (62412) 2000 SY_178 in
three 400-s VR-band CCD exposures taken with the Blanco 4-m
telescope at Cerro Tololo on 2014 Mar. 28 UT. The faint tail was
observed at position angle about 295 degrees and extended about 1'
from the nucleus. Follow-up observations at the Magellan telescope
on May 1 and 2 UT confirm the activity of (62412).
The following orbital elements for (62412) for epoch 2014 Dec.
9.0 TT are based on an 11-opposition solution published on MPO
302401: T = 2013 Mar. 22.36 TT, q = 2.8930 AU, e = 0.0821, Peri.
= 162.69 deg, Node = 329.17 deg, i = 4.74 deg (equinox 2000.0).
(C) Copyright 2014 CBAT
2014 October 30 (9272) Daniel W. E. Green
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