[IAUC] CBET 1143: 20071119 : (16635) 1993 QO

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                                                  Electronic Telegram No. 1143
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT en CFA.HARVARD.EDU (science)
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(16635) 1993 QO
     D. Pray, Carbuncle Hill Observatory, Greene, RI; P. Pravec, P. Kusnirak,
and K. Hornoch, Ondrejov Observatory; Yu. Krugly and V. Chiorny, Institute
of Astronomy, Kharkiv National University, National Academy of Science of
Ukraine; M. Husarik and M. Pikler, Skalnate Pleso Observatory; J. Vilagi, S.
Gajdos, and A. Galad, Modra Observatory; W. Cooney, J. Gross, and D. Terrell,
Sonoita Research Observatory, Sonoita, AZ; N. Gaftonyuk, Simeiz Observatory;
R. Stephens, Goat Mountain Astronomical Research Station, Yucca Valley, CA;
R. Durkee, Minneapolis, MN; 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; F. Colas
and J. Lecacheux, IMCCE and Pic du Midi Observatory; and J. Ries, McDonald
Observatory, report that photometric observations obtained during Sept. 2-
Nov. 9 reveal that minor planet (16635) is a binary system with an orbital
period of 32.25 +/- 0.03 hr.  Additive rotation lightcurves of system's
components have periods 2.2083 +/- 0.0002 and 7.622 +/- 0.002 hr and
amplitudes 0.17 and 0.05 mag, respectively.  Mutual events indicate a lower
limit on the secondary-to-primary mean-diameter ratio of 0.27.  Calibrated
data give an estimated mean absolute magnitude H_R = 14.0 +/- 0.3, assuming G
= 0.15 +/- 0.2.


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                         (C) Copyright 2007 CBAT
2007 November 19                 (CBET 1143)              Daniel W. E. Green