Electronic Telegram No. 5116 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 (2860) PASACENTENNIUM V. Benishek, Belgrade Astronomical Observatory; P. Pravec, H. Kucakova, K. Hornoch, and P. Kusnirak, Ondrejov Observatory; B. Warner, Center for Solar System Studies, Eaton, CO, U.S.A.; P. Sogorb, La Bastide des Jourdans, France; P. Bacci and M. Maestripieri, Astronomical Observatory, San Marcello Pistoiese, Italy; and R. Montaigut and A. Leroy, OPERA Observatory, France, report that photometric observations taken with a 0.35-m telescope at the Sopot Observatory in Serbia, a 0.65-m telescope at Ondrejov Observatory, a 0.35-m telescope at the Center for Solar System Studies, a 0.28-m telescope at the Bastidan Observatory in France, a 0.60-m telescope at the San Marcello Pistoiese Observatory, and a 0.20-m telescope at the OPERA Observatory during 2021 Nov. 16-2022 Mar. 3 reveal that minor planet (2860) is a binary system with an orbital period of 119.7 +/- 0.3 hr. The primary shows a period of 2.6609 +/- 0.0001 hr and has a lightcurve amplitude of 0.17 magnitude at solar phases 17-22 degrees, suggesting a nearly spheroidal shape. Mutual eclipse/occultation events that are 0.18 magnitude deep indicate a secondary- to-primary mean-diameter ratio of 0.42 +/- 0.02. The mean absolute magnitude in the Cousins R photometric system is H_R = 12.50 +/- 0.12, assuming a phase-relation slope parameter G = 0.24 +/- 0.11. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2022 CBAT 2022 April 21 (CBET 5116) Daniel W. E. Green