AAS 204th Meeting, June 2004
Session 64 The Hazardous Solar System and Other Objects
Poster, Wednesday, June 2, 2004, 10:00am-7:00pm, Ballroom

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[64.03] Why Are Hyperbolic Micrometeors No Longer Detected with the Arecibo UHF Radar ?

D.D. Meisel (SUNY-Geneseo), B.D. Bartlett (CIS-RIT), J.D. Mathews (CSSL-Penn State), D. Janches (CIRES-Univ. of Colo.), S. Briczinski (CSSL-Penn State)

Micrometeor detections using the AO UHF radar have been carried out since 1997. During 1997-2000, hyperbolic (presumed extrasolar origin) orbits were obtained for about 3% of the some 30,000 detections (Meisel et al. 2003 on publicly available from the author CD-ROM and Meisel et al. Ap.J. 567, 323 2002a, Ap.J. 579,895 2002b). In one of those papers (2002a), it was predicted that Jupiter was (over the next 3 to 5 years) going to move into the predominant radiant direction of the extrasolar orbits, i.e. the local interstellar bubble. Thus it was expected that the number of extrasolar meteors would diminish. What was not expected was, however, that so far in 2001-2004 no hyperbolic orbits have been found among nearly 20,000 more orbits. At the size range of the detected micrometeors, perturbations by the major planets, solar photons as well as solar wind particle charging and magnetic field interactions must be taken into account. Thus the apparent Jovian perturbing forces (even on elliptical orbits) seems to exceed that provided by gravity alone and is likely to involve action by the extensive Jovian magnetosphere. The situation in the future promises to be even more confused because Saturn will be moving through the same radiant area even as Jupiter moves out. The micrometeor flux is continuing to be closely monitored from AO. This research is supported through NSF Planetary Astronomy and Aeronomy grants AST0205974, AST9801590, and NRA9612055007. Radar time is provided by NAIC, Arecibo Observatory operated for the National Science Foundation through a cooperative agreement with Cornell University.

The author(s) of this abstract have provided an email address for comments about the abstract: meisel@geneseo,edu

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