Video observations, atmospheric path, orbit and fragmentation record of the fall of the Peekskill meteorite |
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Authors: | Z. Ceplecka P. Brown R. L. Hawkes G. Wetherill M. Beech K. Mossman |
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Affiliation: | (1) Academy of Sciences, 251 65 Ondejov Observatory, Czech Republic;(2) Department of Physics, University of Western Ontario, N6A 3K7 London, Ontario, Canada;(3) Department of Physics, Engineering & Geology, Mount Allison University, E0A 3C0 Sackville, New Brunswick, Canada;(4) Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5421 Broad Branch Road NW, 20015 Washington DC, USA;(5) Department of Astronomy, University of Western Ontario, N6A 3K7 London, Ontario, Canada;(6) Department of Physics, Engineering & Geology, Mount Allison University, E0A 3C0 Sackville, New Brunswick, Canada |
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Abstract: | Large Near-Earth-Asteroids have played a role in modifying the character of the surface geology of the Earth over long time scales through impacts. Recent modeling of the disruption of large meteoroids during atmospheric flight has emphasized the dramatic effects that smaller objects may also have on the Earth's surface. However, comparison of these models with observations has not been possible until now. Peekskill is only the fourth meteorite to have been recovered for which detailed and precise data exist on the meteoroid atmospheric trajectory and orbit. Consequently, there are few constraints on the position of meteorites in the solar system before impact on Earth. In this paper, the preliminary analysis based on 4 from all 15 video recordings of the fireball of October 9, 1992 which resulted in the fall of a 12.4 kg ordinary chondrite (H6 monomict breccia) in Peekskill, New York, will be given. Preliminary computations revealed that the Peekskill fireball was an Earth-grazing event, the third such case with precise data available. The body with an initial mass of the order of 104 kg was in a pre-collision orbit with a = 1.5 AU, an aphelion of slightly over 2 AU and an inclination of 5. The no-atmosphere geocentric trajectory would have lead to a perigee of 22 km above the Earth's surface, but the body never reached this point due to tremendous fragmentation and other forms of ablation. The dark flight of the recovered meteorite started from a height of 30 km, when the velocity dropped below 3 km/s, and the body continued 50 km more without ablation, until it hit a parked car in Peekskill, New York with a velocity of about 80 m/s. Our observations are the first video records of a bright fireball and the first motion pictures of a fireball with an associated meteorite fall. |
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Keywords: | meteorite fall fireball Earth-grazing video-records trajectory orbit Peekskill |
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