Electronic Telegram No. 4157
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
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Prepared using the Tamkin Foundation Computer Network


(31450) 1999 CU9
        D. Pray, Sugarloaf Mountain Observatory, South Deerfield, MA, U.S.A.;
P. Pravec, K. Hornoch, J. Vrastil and H. Kucakova, Ondrejov Observatory;
V. Benishek, Belgrade Astronomical Observatory, Serbia; R. Roy, Observatoire
de Blauvac, France; R. Behrend, Geneva Observatory; D. Romeuf,
Chapdes-Beaufort, France; B. Warner, Center for Solar System Studies, Eaton,
CO, U.S.A.; A. Scholz and G. Hodosan, Observatory of the University of St.
Andrews, U.K.; J. Pollock, Appalachian State University; R. Montaigut and A.
Leroy, OPERA Observatory, France; and D. Reichart and J. Haislip, University
of North Carolina, Chapel Hill, report that photometric observations obtained
during Sept. 5-Oct. 13 reveal that minor planet (31450) is a binary system
with an orbital period of 53.47 +/- 0.07 hr.  The primary shows a period of
3.4116 +/- 0.0003 hr, and has a lightcurve amplitude of 0.24 mag at solar
phases 5-9 deg.  Mutual secondary eclipse/occultation events that are 0.05
magnitude deep indicate a lower limit on the secondary-to-primary
mean-diameter ratio of 0.22.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2015 CBAT
2015 October 26                  (CBET 4157)              Daniel W. E. Green