THE ORIGIN OF CHONDRULES AT JOVIAN RESONANCES

Isotopic dating indicates that chondrules were produced a few million years after the solar nebula formed. This timing is incompatible with dynamical lifetimes of small particles in the nebula and short time sc ales for the formation of planetesimals. Temporal and dynamical constr aints can be reconciled if chondrules were produced by heating of debr is from disrupted first-generation planetesimals. Jovian resonances ca n excite planetesimal eccentricities enough to cause collisional disru ption and melting of dust by bow shocks in the nebular gas. The ages o f chondrules may indicate the limes of Jupiter's formation and dissipa tion of gas from the asteroidal region.