Abstract

D. Higgins, Canberra, Australia; P. Pravec, P. Kusnirak, and K. Hornoch, Ondrejov Observatory; M. Husarik, M. Pikler, and G. Cervak, Skalnate Pleso Observatory; D. Pray, Carbuncle Hill Observatory, Greene, RI; S. Gajdos, Modra Observatory; Yu. Krugly, Institute of Astronomy, Kharkiv National University, National Academy of Science of Ukraine; A. Marshalkina, Ulugh Beg Astronomical Institute, Uzbek Academy of Sciences; R. Stephens, Goat Mountain Astronomical Research Station, Yucca Valley, CA; F. Colas, Pic du Midi Observatory; and W. Cooney, J. Gross, and D. Terrell, Sonoita Research Observatory, Sonoita, AZ, report that photometric observations obtained during Oct. 4-Nov. 7 reveal that minor planet (8116) is a binary system with an orbital period of 36.15 +/- 0.02 hr. The primary shows a period of 3.6169 +/- 0.0002 hr, and it has a lightcurve amplitude of 0.09 mag, suggesting a nearly spheroidal shape. Mutual eclipse/occultation events indicate a lower limit on the secondary-to-primary mean-diameter ratio of 0.33. Calibrated data give an estimated mean absolute magnitude H_R = 13.52 +/- 0.13, assuming G = 0.15 +/- 0.2.