V. Benishek, Belgrade Astronomical Observatory; P. Pravec, Ondrejov Observatory; F. Pilcher, Organ Mesa Observatory, Las Cruces, NM, U.S.A.; A. Marchini, R. Papini, and F. Salvaggio, Dipartimento di Scienze Fisiche, Della Terra e Dell’Ambiente, University of Siena; J. Oey, Blue Mountains Observatory, Leura, NSW, Australia; D. Pray, Sugarloaf Mountain Observatory, South Deerfield, MA, U.S.A.; R. Durkee, Shed of Science South Observatory, Pontotoc, TX, U.S.A.; W. Cooney, J. Gross, and D. Terrell, Sonoita Research Observatory, Sonoita, AZ, U.S.A.; R. Goncalves, Linhaceira Observatory, Tomar, Portugal; A. Aznar, Isaac Aznar Observatory, Alcublas, Valencia, Spain; C. Odden, Phillips Academy, Andover, MA, U.S.A.; and J. Kemp, Middlebury College, Middlebury, VT, U.S.A., report that photometric
observations taken with a 0.35-m telescope at the Sopot Observatory in Serbia, a 0.35-m telescope at the Organ Mesa Observatory, a 0.30-m telescope at the Astronomical Observatory of the University of Siena, a 0.35-m telescope at the Blue Mountains Observatory, a 0.50-m telescope at the Sugarloaf Mountain Observatory, a 0.50-m telescope at the Shed of Science South Observatory, a 0.50-m telescope at the Sonoita Research Observatory, a 0.35-m telescope at the Linhaceira Observatory, a 0.35-m telescope at the Isaac Aznar Observatory, and a 0.50-m telescope at the Mittelman Observatories at New Mexico Skies during Mar. 20-May 19 reveal that minor planet (2500) is a binary system with an orbital period of 169.1 +/- 0.3 hr. The primary shows a period of 2.75123 +/- 0.00009 hr and has a lightcurve amplitude of 0.19 magnitude at solar phases 2-17 degrees, suggesting a nearly spheroidal shape. Mutual eclipse/occultation events that are 0.15 to 0.27 magnitude deep indicate a secondary-to-primary mean-diameter ratio of 0.39 +/- 0.02.
NOTE: These ‘Central Bureau Electronic Telegrams’ are sometimes superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2020 CBAT2020 June 7 (CBET 4791) Daniel W. E. Green