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L. Mahoney-Hopping, S. Dermott, T. Kehoe (Univ. of Florida)
Our model of the solar system dust bands shows that the near-ecliptic and ten-degree bands result mainly from the relatively recent (< 10 Ma) catastrophic disruptions of the parent bodies of the Veritas family and Karin cluster, with an additional small contribution from the Themis family. The model incorporates results from numerical simulations of the orbital evolution of dust particles from these sources, with diameters up to 500 \mum. The effect of particle-particle collisions becomes increasingly important as particle size and hence Poynting-Robertson drag lifetimes increase. We simulate this by producing a set of individual models with discrete semi-major axis ranges that have independent size-frequency distributions. These ``slices'' are then combined using a weighting function to account for the change in cross-sectional area of the particles as a function of semi-major axis. By comparing this combined model to IRAS observations, we can adjust the required cross-sectional area of material in each slice and therefore calculate the total dust band contribution to the zodiacal cloud. Whether this quantity of asteroidal material is sufficient to dominate the zodiacal cloud and account for its observed structure is discussed. Some of these particles are ultimately accreted by Earth, and therefore a portion of the IDPs originate from one of these known asteroidal sources. Only the large particles (\lesssim 1000 \mum) created in the original disruption of the parent body, along with smaller particles resulting from the collisional fragmentation of some of these larger particles, will currently reside in the inner solar system. Therefore, only the tail-end of the waves of dust particles are observed. It follows that collisional disruption of sizable asteroids dramatically increases the cross-sectional area of material in the zodiacal cloud and thus results in large variations in the accretion rate of IDPs by Earth, with potentially drastic consequences for Earth's climate.
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.