Electronic Telegram No. 4339
Central Bureau for Astronomical Telegrams
Mailing address: Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: email@example.com (alternate firstname.lastname@example.org)
Prepared using the Tamkin Foundation Computer Network
[Editor's note: this text replaces that on CBET 4338 (designation error)].
F. Manzini, Stazione Astronomico di Sozzago, Italy; R. Behrend, Geneva
Observatory; E. Frappa, L. Brunetto, Z. Challita, and F. Colas, Institut de
Mecanique Celeste et de Calcul des Ephemerides (IMCCE); A. Kryszczynska,
Poznan, Poland; M. Castets, B. Tregon, A. Leroy, A. Klotz, L. Bernasconi,
A. Debackere, B. Mallecot, C. Rinner, and F. Vachier, IMCCE; J.-G. Bosch,
J.-P. Godard, and J. Strajnic, "Le Ciel Comme Laboratoire" project in France;
and a group of students involved with "Le Ciel Comme Laboratoire" project
(including M. Tlouzeau, M. Irzyk, P. Antonini, P. Barroy, R. Anquetin, R. Roy,
R. Montaigut, R. Goncalves, S. Charbonnel, A. Canac, J. Canac, J. Chandre, A.
Cucchietti, O. Galmard, N. Hermite, D. Hernandez, L. Jacquemin, N. Kibar, M.
Laage, E. Ayala, A Ruiz, Ch. Evan Sanna, B. Trochon, G. Vallauri, B. Veran,
D. Vuleta, L. Klidas, T. Billeri, N. Gauthier, R. Faissal, G. Genero, Y.
Moutier, Th. Cassart, J.-Ph. Garcia, R. Trauchessec, B. Tissot, D. Neel, L.
Daverio, C. Courson, and J.-B. Bellier) report that they obtained lightcurves
of the minor planet (12008) during July 2007, which were typical of binary
synchronous asteroids (a regular, smooth, sinusoidal-like curve with two
peaks per rotation, but with additional very-fast V-shaped dimming during
both minima of brightness. The period is around 1.371 day. The monitoring
until January 2008 showed a regular evolution of the signature of mutual
phenomenona. Other observations were obtained between August and October
2010, showing lightcurves with similar properties. In December 2013, the
amplitude of variation was similar to those of the other oppositions, but
some events were possibly missed. As observed on 2016 Dec. 2 and 7, the
mutual phenomenona are 0.5-magnitude deep and their duration is around 4
hours; an observed brightness minimum occurred on Dec. 6.930 UT. These are
indications that the mutual orbit of the system components is close to the
ecliptic plane, like that of minor planet (4492) Debussy. Observations of
stellar occultations by both components seem to be the easiest way to
determine shapes, sizes, and separation of this pair of bodies. The ratio
of the sizes is most probably between 0.5 and 1. An ephemeris of the events
and rotational lightcurves can be examined at the following website URL:
http://obswww.unige.ch/~behrend/page5cou.html#012008. Observations were
conducted at private observatories as well as at Haute-Provence, Pic du Midi,
the Haleakala "Faulkes North" telescope, and the Observatoire de Buthiers.
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2016 CBAT
2016 December 23 (CBET 4339) Daniel W. E. Green