Electronic Telegram No. 5642
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


(3918) BREL
     M. Deldem, Les Barres Observatory, Lamanon, France; R. Behrend, Geneva
Observatory; P. Pravec and P. Fatka, Ondrejov Observatory; R. Durkee, Shed of
Science South Observatory, Pontotoc, TX, U.S.A.; N. Ruocco, Osservatorio
Astronomico Nastro Verde, Sorrento, Italy; O. Labrevoir, Centre d'Astronomie
de Saint-Michel, France; V. Benishek, Belgrade Astronomical Observatory; D.
Augustin, Anglet, France; and K. Ergashev and O. Burkhonov, Ulugh Beg
Astronomical Institute, Tashkent, Uzbekistan, report that photometric
observations taken with a 0.20-m telescope at the Les Barres Observatory, a
0.50-m telescope at the Shed of Science South Observatory, a 0.35-m telescope
at the Osservatorio Astronomico Nastro Verde, a 0.6-m telescope at the Centre
d'Astronomie de Saint-Michel, a 0.35-m telescope at the Sopot Observatory in
Serbia, a 0.35-m telescope at e-EyE Observatory in Spain, and a 0.6-m
telescope at Maidanak Observatory in Uzbekistan during Aug. 25-Oct. 29 reveal
that minor planet (3918) is a binary system with an orbital period of 16.655
+/- 0.007 hr. The primary has a period of 3.0970 +/- 0.0003 hr and a
light-curve amplitude of 0.26 magnitude at solar phases 3-6 degrees.  Mutual
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
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                         (C) Copyright 2025 CBAT
2025 December 2                  (CBET 5642)              Daniel W. E. Green