Electronic Telegram No. 4279
Central Bureau for Astronomical Telegrams
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(85990) 1999 JV_6
     J. D. Giorgini, Jet Propulsion Laboratory (JPL); P. A. Taylor and L. A.
Rodriguez-Ford, Arecibo Observatory; A. Rozek and S. C. Lowry, Centre for
Astrophysics and Planetary Science, University of Kent; M. C. Nolan, Lunar
and Planetary Laboratory, University of Arizona; and M. Brozovic and
L. A. M. Benner, JPL, report that a non-gravitational acceleration has been
detected influencing the motion of minor planet (85990).  Recently reduced
Arecibo (2380-MHz, 12.6-cm) round-trip delay measurements of (85990) that
were obtained on Jan. 14, 17, and 19 yield offsets of -5.6 +/- 1.0, -8.4 +/-
0.5, and -11.4 +/- 0.5 x 10^{-6} second relative to the orbit predicted from
945 initial plane-of-sky angular measurements from optical observations
spanning 1999-2016, combined with four prior radar-delay measurements
reported from Goldstone (8560-MHz, 3.5-cm) in 2016 and four from Arecibo in
2015 (JPL orbit solution 197).  This 4-sigma delay offset (relative to that
2016 orbital prediction) is dynamically consistent with a heliocentric
transverse non-gravitational acceleration over the data arc of -1.6 +/- 0.2
x 10^{-12} m/s^2, estimated in JPL orbit solution 207 (from 2016 May 19)
using a combined astrometric dataset consisting of 965 optical measurements
(1999-2016) with eleven radar delay measurements.  Physical parameters
derived from 7.5-meter-resolution radar imaging are being reported
separately [Rozek and Lowry et al., "Shape and spin-state modelling of the
NEA (85990) 1999 JV6 from radar and optical observations", submitted, 4th
Workshop on Binaries in the Solar System, Prague, 2016 June 21-23].


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2016 CBAT
2016 May 27                      (CBET 4279)              Daniel W. E. Green