S/2004 (45) 1

F. Marchis and M. Baek, University of California at Berkeley; and P. Descamps, J. Berthier, D. Hestroffer, and F. Vachier, Institut de Mecanique Celeste et de Calcul des Ephemerides, Paris, report the discovery of a new satellite orbiting (45) Eugenia. S/2004 (45) 1 was detected after careful analysis of three observations collected with K-band filters using the Very Large Telescope 'YEPUN' and its adaptive-optics system (NACO) on 2004 Feb. 14.15404, 15.14620, and 16.15435 UT, the satellite appearing at a distance of about 0".4 from the primary in p.a. 156, 321, and 124 degrees, respectively. Based on the integrated brightness ratio of about 7.9 between the satellite and the primary, the diameter of S/2004 (45) 1 is estimated to be about 6 km. The orbital parameters of this satellite give a mass for the system in agreement with the mass derived from the study of previously known satellite, (45) Eugenia I (Petit-Prince; cf. IAUCs 7129, 7503).