Lightcurve Survey of V-type Asteroids. I. Observations until Spring 2004
  To examine the distribution of rotational rates for chips of asteroid 4 Vesta, lightcurve observation of seven V-type asteroids (2511 Patterson, 2640 Hallstorm, 2653 Principia, 2795 Lapage, 3307 Athabasca, 4147 Lennon, and 4977 Rauthgundis) were performed from fall 2003 to spring 2004. Distribution of spin rates of V-type main-belt asteroids from the past and our observations have three peaks. This result implies that age of catastrophic impact making Vesta family may be not as young as Karin and Iannini families but as old as Eos and Koronis families. 
Sunao Hasegawa, Seidai Miyasaka, Chiaki Yoshizumi, Tomohiko Sekiguchi,   Yuki Sarugaku, Setsuko Nishihara, Kouhei Kitazato, ...
astro-ph.EP