Collaborative Research: Arecibo Radar Studies of Zodiacal and Interstellar Dust in the Solar System.

AST 0205848

Mathews

Dr. John Mathews, at Penn State University, in collaboration with Dr. David Meisel, at State University of New York at Geneseo, will conduct a 3-year observational and analysis/modeling study of small particles in the Solar System based on radar micrometeor observations performed at the Arecibo Observatory. Knowledge of the distribution, sources, and gravitational, electrodynamical evolution of interplanetary dust particles (IDPs) in the ~0.2-100 micron size range is critical to the planetary sciences and-as extrasolar and interstellar particles are also present-to local galactic science.

The Arecibo Observatory (AO) UHF radar has proven to be uniquely suited for ground-based micrometeor observations that yield velocity, deceleration, and radiant information-and thus orbits-of large numbers of interplanetary and hyperbolic dust particles. Observational results now extend from 1997 through the present with a steadily evolving technique that now yields meteoroid Doppler speeds with instantaneous accuracies of as small as 10 m/sec (with meteoroid speeds ranging over 10-90 km/sec thus far). This combined with a sorting mechanism based on classical, in-atmosphere meteoroid dynamics, clearly distinguishes down-the-beam particles from those meteoroids with a significant across-the-beam velocity component. The new effort extends these studies to details of IDP distribution/evolution in the solar system and considers the role of the interstellar particle flux to the solar system as well as local galactic processes/features illuminated by this flux.

The new observational/analysis/modeling study funded with this award will continue providing routine sampling of IDPs including the expected earth-crossing asteroidal-orbit particles, interstellar particles (ISPs), Jovian perturbed and/or derived particles, and low-mass b particles ejected by radiation pressure from the inner solar system. As the database of ISPs grows, these researchers will continue theoretical/modeling studies of the flux and origins of the largest of the interstellar particles. Thus far they can account for all AO ISPs as being products of the same supernova that

produced the Geminga pulsar. This effort has involved and will continue to involve undergraduates from SUNY-Geneseo, Penn State, and other institutions and graduate students from Penn State as well as the staff of Arecibo Observatory and other organizations. Results from these efforts appear in several courses including electromagnetics, astrophysics, and plasmas at both Geneseo and Penn State.

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