Electronic Telegram No. 4387
Central Bureau for Astronomical Telegrams
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(2881) MEIDEN
     T. Polakis, Command Module Observatory, Tempe, AZ, U.S.A.; B. A. Skiff,
Lowell Observatory; P. Pravec, Ondrejov Observatory; and B. D. Warner, Center
for Solar System Studies, Eaton, CO, U.S.A., report that photometric
observations taken with a 0.32-m telescope at the Command Module Observatory,
and 0.7-m, 1.1-m, and 1.8-m telescopes at the Lowell Observatory during 2017
Mar. 24 to Apr. 23 reveal that minor planet (2881) is a binary system with an
orbital period of 20.42 +/- 0.01 hr.  Mutual eclipse/occultation events that
are 0.09- to 0.15-magnitude deep indicate a secondary-to-primary mean-
diameter ratio of 0.29 +/- 0.02.  The eclipsing/occulting secondary has a
synchronous rotation with an observed lightcurve amplitude of 0.06 mag.
Superposed to the eclipse/occultation lightcurve are two rotational light
curves with periods 3.48011 +/- 0.00004 and 3.7324 +/- 0.0001 hr with
amplitudes of 0.12 and 0.06 mag, respectively; their behavior during the
mutual events -- they are present with unchanged shapes during the events --
indicates that neither of them belongs to the eclipsing/occulting secondary.
This suggests that, while one of the short periods belongs to the primary,
the other belongs to a third body in the system (compare with other cases of
this kind in Pravec et al. 2016, Icarus 267, 267).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2017 CBAT
2017 April 29                    (CBET 4387)              Daniel W. E. Green