Electronic Telegram No. 5617
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)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


(6690) MESSICK
     V. Benishek, Belgrade Astronomical Observatory; P. Pravec, Ondrejov
Observatory; A. Leroy, Uranoscope de l'Ile de France, Gretz-Armainvilliers,
France; C. Bihbah, Societe Astronomique de Tunisie, Tunisia; S. Sylla,
Universite Cheikh Anta Diop, Dakar, Senegal; N. Tovolahy and M. Avotra,
Haikintana Astronomy Association, Madagascar; F. Vachier, Observatoire de
Paris; J. Oey, Blue Mountains Observatory, Leura, NSW, Australia; R. Durkee,
Shed of Science South Observatory, Pontotoc, TX, U.S.A.; D. Augustin, Anglet,
France; and A. Klotz, J. Berthier, and P. Thierry, Observatoire des Makes,
Reunion, report that photometric observations taken with a 0.35-m telescope at
the Sopot Observatory in Serbia, a 0.36-m telescope at Ecole du Monde Besely
in Madagascar, a 0.6-m telescope at the Observatoire des Makes, a 0.35-m
telescope at the Blue Mountains Observatory, a 0.50-m telescope at the Shed of
Science South Observatory, and a 0.35-m telescope at e-EyE Observatory in
Spain during Aug. 14-Sept. 24 reveal that minor planet (6690) is a binary
system with an orbital period of 29.75 +/- 0.02 hr.  The primary shows a
period of 3.0248 +/- 0.0001 hr and has a light=curve amplitude of 0.24
magnitude at solar phases 2-12 degrees.  Mutual eclipse/occultation events
that are 0.12 magnitude deep indicate a secondary-to-primary mean-diameter
ratio of 0.34 +/- 0.02.


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2025 October 7                   (CBET 5617)              Daniel W. E. Green