Electronic Telegram No. 5446
Central Bureau for Astronomical Telegrams
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(7930) 1987 VD
     V. Benishek, Belgrade Astronomical Observatory; P. Pravec, P. Kusnirak,
and P. Fatka, Ondrejov Observatory; K. Ergashev, O. Burkhonov, and Sh.
Ehgamberdiev, Ulugh Beg Astronomical Institute, Tashkent, Uzbekistan; A.
Leroy, Observatoire de Besely, Ecole du Monde, Mahajanga, Madagascar; R.
Durkee, Shed of Science South Observatory, Pontotoc, TX, USA; and N. Ruocco,
Osservatorio Astronomico Nastro Verde, Sorrento, Italy, report that
photometric observations taken with a 0.35-m telescope at the Sopot
Observatory in Serbia, a 0.6-m telescope at Maidanak Observatory in
Uzbekistan, a 0.36-m telescope at the Observatoire de Besely, a 0.50-m
telescope at the Shed of Science South Observatory, and a 0.35-m telescope
at the Osservatorio Astronomico Nastro Verde during July 17-Sept. 11 reveal
that minor planet (7930) is a binary system with an orbital period of
14.615 +/- 0.005 hr.  Mutual eclipse/occultation events that are 0.07
magnitude deep indicate a lower limit on the secondary-to-primary
mean-diameter ratio of 0.26.  Superimposed to the eclipse/occultation
lightcurve are two rotational lightcurves with periods 2.5746 +/- 0.0002 hr
and 5.5600 +/- 0.0008 hr, with amplitudes of 0.10 and 0.07 mag,
respectively; their behavior in the mutual events -- they are present with
unchanged shapes during the events -- indicates that none 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; and Pravec et al. 2019, Icarus 333, 429).


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2024 September 15                (CBET 5446)              Daniel W. E. Green