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| Titel |
Meteoroid velocity distribution derived from head echo data collected at Arecibo during regular world day observations |
| VerfasserIn |
M. P. Sulzer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 4, no. 4 ; Nr. 4, no. 4 (2004-06-28), S.947-954 |
| Datensatznummer |
250001831
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| Publikation (Nr.) |
 copernicus.org/acp-4-947-2004.pdf |
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| Zusammenfassung |
| We report the observation and analysis of ionization flashes associated with
the decay of meteoroids (so-called head echos) detected by the Arecibo 430
MHz radar during regular ionospheric observations in the spring and autumn
equinoxes. These two periods allow pointing well-above and nearly-into the
ecliptic plane at dawn when the event rate maximizes. The observation of many
thousands of events allows a statistical interpretation of the results, which
show that there is a strong tendency for the observed meteoroids to come from
the apex as has been previously reported (Chau and Woodman, 2004). The velocity
distributions agree with Janches et al. (2003a) when they are directly
comparable, but the azimuth scan used in these observations allows a new
perspective. We have constructed a simple statistical model which takes
meteor velocities as input and gives radar line of sight velocities as
output. The intent is to explain the fastest part of the velocity
distribution. Since the speeds interpreted from the measurements are
distributed fairly narrowly about nearly 60 km s-1, double the
speed of the earth in its orbit, is consistent with the interpretation that
many of the meteoroids seen by the Arecibo radar are moving in orbits about
the sun with similar parameters as the earth, but in the retrograde
direction. However, it is the directional information obtained from the
beam-swinging radar experiment and the speed that together provide the
evidence for this interpretation. Some aspects of the measured velocity
distributions suggest that this is not a complete description even for the
fast part of the distribution, and it certainly says nothing about the slow
part first described in Janches et al. (2003a). Furthermore, we cannot conclude
anything about the entire dust population since there are probably selection
effects that restrict the observations to a subset of the population. |
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