Electronic Telegram No. 5385
Central Bureau for Astronomical Telegrams
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(3643) TIENCHANGLIN
     D. Augustin, Anglet, France; M. Deldem, Les Barres Observatory, Lamanon,
France; R. Behrend, Geneva Observatory; and R. Dosso and O. Ba, Anglet,
France, report that photometric observations taken with a 0.35-m telescope at
E-Eye, Fregenal de la Sierra, Spain; a 0.28-m telescope at Les Barres
Observatory in France; and a 0.50-m "IRIS-IPhU" telescope at L'Observatoire
de Haute-Provence during 2023 Dec. 17-2024 Jan. 27 reveal that minor planet
(3643) is a binary system with an orbital period of 28.34 +/- 0.02 hr.  The
primary shows a period of 2.86728 +/- 0.00005 hr and has a light-curve
amplitude of 0.10 magnitude at solar phases 9-13 degrees.  Several mutual
eclipse/occultation events were observed, with a 0.08-magnitude drop for a
primary event and 0.05-magnitude drop for a secondary event:  2023 Dec. 21.82
UT, primary event, E-Eye; Dec. 24.17, primary event, E-Eye; 2024 Jan. 2.03,
secondary event, Les Barres Observatory; Jan. 7.93, secondary event, E-Eye;
10.89, primary event, E-Eye; 20.92, primary event, E-Eye.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2024 CBAT
2024 April 22                    (CBET 5385)              Daniel W. E. Green