Electronic Telegram No. 5502
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


(1934) JEFFERS
     P. Pravec, K. Hornoch, H. Kucakova, and P. Kusnirak, Ondrejov
Observatory; D. Pray, Sugarloaf Mountain Observatory, South Deerfield, MA,
U.S.A.; R. Durkee, Shed of Science South Observatory, Pontotoc, TX, U.S.A.;
and D. Augustin, Anglet, France, report that photometric observations taken
with a 0.65-m telescope at Ondrejov Observatory, a 0.63-m telescope at the
Sugarloaf Mountain Observatory, a 0.50-m telescope at the Shed of Science
South Observatory, and a 0.35-m telescope at e-EyE Observatory in Spain
during 2024 Dec. 26-2025 Jan. 27 reveal that minor planet (1934) is a binary
system with an orbital period of 34.55 +/- 0.02 hr.  The primary has a period
of 6.0450 +/- 0.0006 hr and a lightcurve amplitude of 0.11 magnitude at
solar phase 10 degrees, suggesting a nearly spheroidal shape.  Mutual
eclipse/occultation events that are 0.11 magnitude deep indicate a
secondary-to-primary mean-diameter ratio of 0.33 +/- 0.02.  The secondary
appears synchronous and has a light-curve amplitude (in the combined
primary-plus-secondary light curve) of 0.07 mag, suggesting an elongated shape
with an equatorial-axis ratio of 1.7 +/- 0.2.  The system's mean absolute
magnitude in the Cousins R photometric system H_R = 11.98 +/- 0.11, assuming a
phase-relation slope parameter G = 0.24 +/- 0.11.  The work at Ondrejov
Observatory was done in the framework of their NEOSource project, supported by
the "Praemium Academiae" grant from the Academy of Sciences of the Czech
Republic.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2025 CBAT
2025 February 10                 (CBET 5502)              Daniel W. E. Green