EISCAT observations of meteoric fragmentation

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EISCAT observations ofmeteoric fragmentation

• Johan Kero, Csilla Szasz and Asta
  Pellinen-Wannberg
• (Swedish Institute of Space Physics, Kiruna,
  Sweden)
• Gudmund Wannberg and Assar Westman
• (EISCAT Scientific Association, Kiruna, Sweden)

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Outline of the talk

• Meteoric fragmentation processes
• From fireballs to dust...
• Observations with EISCAT
• Fragmentation of small meteoroids...

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Optical brightness pulsations
2004-11-21 Leonid campaign with ALIS
ACKNOWLEDGEMENTS Björn Gustavsson and the ALIS
team
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Fireball flickering

• Peekskill, October 9, 1992

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Forms of fragmentation
Table from Bronshten, Physics of Meteoric
Phenomena, Kluwer, 1983
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EISCAT UHF 2004-12-21 2005-06-21 2005-09-22
(?)
EISCAT VHF 2003-11-26
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TROMSØ
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Assumption One meteoroid broke up into
two major fragments Conclusions that may
be drawn under the assumption is that the
separation...
...distance was increasing with constant
acceleration 0.88 km/s2
...occurred 0.1 s eller 4 km before they reached
the centre of the radar beam
...distance was 1.6 m when they entered the radar
beam
...distance was 9.6 m when they left the radar
beam
photo Csilla Szasz