Electronic Telegram No. 1147
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


(32039) 2000 JO23
     D. Pray, Carbuncle Hill Observatory, Greene, RI; P. Pravec, P. Kusnirak
and K. Hornoch, Ondrejov Observatory; D. Higgins, Canberra, Australia; W.
Cooney, J. Gross, and D. Terrell, Sonoita Research Observatory, Sonoita,
AZ; J. Oey, Leura, N.S.W., Australia; A. Galad, L. Kornos, S. Gajdos, and J.
Vilagi, Modra Observatory; R. Stephens, Goat Mountain Astronomical Research
Station, Yucca Valley, CA; F. Marchis and M. Baek, SETI Institute; B.
Macomber, University of California at Berkeley; V. Reddy, Department of
Earth System Science and Policy, University of North Dakota, Grand Forks;
and M. Husarik and M. Pikler, Skalnate Pleso Observatory, report that
photometric observations obtained during Sept. 3-Nov. 8 reveal that minor
planet (32039) is a binary system.  Mutual events observed on Sept. 16.3,
Oct. 1.3, and 8.8 suggest an orbital period of 360 hr, and their depth of
0.32 mag indicates a lower limit on the secondary-to-primary mean-diameter
ratio of 0.58.  Two additive lightcurve components have been observed, one
with a period of 3.2990 +/- 0.0002 or 6.5979 +/- 0.0009 hr and amplitude
0.05 mag, and the other one with a period of 11.099 +/- 0.003 hr and
amplitude 0.08 mag.  The former appears to be a rotation lightcurve of the
primary, but an interpretation of the latter lightcurve component as
belonging to the secondary is less certain and model-dependent.  Calibrated
data give an estimated mean absolute magnitude H_R = 15.39 and slope
parameter G = 0.25, both with formal uncertainties of 0.03.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2007 CBAT
2007 November 23                 (CBET 1147)              Daniel W. E. Green