Production of star-grazing and star-impacting planetesimals via orbital migration of extrasolar planets

During orbital migration of a giant extrasolar planet via ejection of plane tesimals (as studied by Murray et al. in 1998), inner mean-motion resonance s can be strong enough to cause planetesimals to graze or impact the star. We integrate numerically the motions of particles which pass through the 3: 1 or 4:1 mean-motion resonances of a migrating Jupiter-mass planet. We find that many particles can be trapped in the 3:1 or 4:1 resonances and pumped to high enough eccentricities that they impact the star. This implies that for a planet migrating a substantial fraction of its semimajor axis, a fra ction of its mass in planetesimals could impact the star. This process may be capable of enriching the metallicity of the star at a time when the star is no longer fully convective. Upon close approaches to the star, the surf aces of these planetesimals will be sublimated. Orbital migration should ca use continuing production of evaporating bodies, suggesting that this proce ss should be detectable with searches for transient absorption lines in you ng stars. The remainder of the particles will not impact the star but can b e ejected subsequently by the planet as it migrates further inward. This al lows the planet to migrate a substantial fraction of its initial semimajor axis by ejecting planetesimals.