parent body. Thus the original object had a rotation rate of about 1–3 days. Evolutionary models of this spread in the rotation rate of the Eos family implies that this group may be comparable to the age of the Solar System. Numerical simulations of the collision that created the Eos family suggest that the smaller body was about a tenth the mass of the parent and struck from a direction out of the ecliptic plane. The parent object had an estimated diameter of 240 km. The best fit model implies a family age of 1.1 billion years. Members of the Eos family include the asteroids 221 Eos, 339 Dorothea, 450 Brigitta, 513 Centesima, 562 Salome, 633 Zelima, 639 Latona, 651 Antikleia, 653 Berenike, 661 Cloelia, 669 Kypria, 742 Edisona, 798 Ruth, 807 Ceraskia, 876 Scott and 890 Waltraut. Not all fragments of the original parent body have remained in the orbital zone occupied by the Eos family. Spectroscopic analysis has shown that some of these asteroids are now located in the 9:4 mean-motion resonance with Jupiter. These fugitives appear relatively young compared to the other family members. References