AAS 95-315

Dactyl Orbit Determination Analysis

D. V. Byrnes and L. A. D'Amario, Jet Propulsion Laboratory, Pasadena, CA

Abstract

Galileo's recent discovery that the asteroid Ida has a satellite (now known
as Dactyl) has allowed, for the first time, an accurate estimate of an
asteroid's bulk density. Dactyl and Ida appear in 47 image returned from the
Ida encounter. The locations of Ida and Dactyl in these images were used to
estimate Dactyl's orbit as a function of Ida's mass. Interestingly, a wide
range of possible orbits fit the observational data equally well, so
dynamical and statistical arguments are necessary to constrain the range of
possible orbits and hence the mass of Ida.