Electronic Telegram No. 5213 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 (2037) TRIPAXEPTALIS V. Benishek, Belgrade Astronomical Observatory; P. Pravec, Ondrejov Observatory; and R. Durkee, Shed of Science South Observatory, Pontotoc, TX, U.S.A., report that photometric observations taken with a 0.35-m telescope at the Sopot Observatory in Serbia and a 0.50-m telescope at the Shed of Science South Observatory during 2022 Oct. 28-Dec. 1 reveal that minor planet (2037) is a binary system with an orbital period of 26.25 +/- 0.02 hr. The primary shows a period of 2.49535 +/- 0.00006 hr and has a lightcurve amplitude of 0.12 magnitude at solar phases 4-16 degrees, suggesting a nearly spheroidal shape. Mutual eclipse/occultation events that are 0.05 to 0.10 magnitude deep indicate a secondary-to-primary mean-diameter ratio of 0.22 +/- 0.02. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 February 2 (CBET 5213) Daniel W. E. Green