An Observing Campaign of the Mutual Events Within (617) Patroclus-Menoetius Binary Trojan System

Jerome Berthier, F. Marchis, P. Descamps, M. Assafin, S. Bouley, F. Colas, G. Dubos, J. P. Emery, P. De Cat, J. A. Farrell, A. Leroy, T. Pauwels, J. T. Pollock, V. Reddy, P. V. Sada, P. Vingerhoets, F. Vachier, R. Vieira-Martins, M. H. Wong, D. E. ReichartK. M. Ivarsen, J. A. Crain, A. P. LaCluyze, M. C. Nysewander

Research output: Contribution to journalArticlepeer-review


In 2006-2007, the binary Trojan system (617) Patroclus-Menotius reached one of its annual equinoxes. As a consequence, the system underwent a 6 months season of mutual eclipses and occultations. We organized a campaign of observations of these mutual events mostly centered along the first semester of 2007. We took advantage of an orbit solution of the similary-sized binary system published by Marchis et al. (Nature, 2006) to predict the timing of mutual eclipses and occultations observable from January to July 2007. During the campaign, the magnitude of Patroclus system varied from 15.8 to 16.6 and its solar phase from 9°.5 to 2°.7 at opposition (end of March). The amplitude of the events ranged between 0.2 and 0.3 magnitude. A large number of stations around the world were involved in the campaign and 20 lightcurves with mutual events signature were collected ( With such favorable circumstances, photometric observations of the events will provide tight constraints regarding physical properties of the system such as sizes, shapes, sidereal spin period and surface composition. Combining AO observations collected at Keck and Gemini with this lightcurve data, we have refined the orbital parameters of the binary system to an unprecedented accuracy. We will present these findings, the determination of the sizes and shapes, and other results from the data analysis. This material is partly based upon work supported by the National Aeronautics and Space Administration issue through the Science Mission Directorate Research and Analysis Programs number NNG05GF09G.
Original languageEnglish
JournalAmerican Astronomical Society, DPS meeting #50
Publication statusPublished - 1 Oct 2007
Externally publishedYes


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