[IAUC] CBET 1166: 20071212 : LEONID METEORS 2007

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                                                  Electronic Telegram No. 1166
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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LEONID METEORS 2007
     The following revised text replaces that on CBET 1153:

     P. Jenniskens, SETI Institute, reports, from observations at Fremont
Peak Observatory in California, a strong return of the Leonid shower on
the nights of Nov. 17-19.  On Nov. 18.8 UT, the zenithal hourly rate (ZHR)
was measured at 23 +/- 4 meteors/hr, above the annual peak rate of ZHR =
13/hr (Jenniskens 1996, Meteoritics Planet. Sci. 31, 177).  Visual
observations collected by the International Meteor Organization, and posted
in near-real time, show a broad enhancement of rates centered at solar
longitude 236.0 +/- 0.2 deg (Nov. 18.85 +/- 0.20), with a duration FWHM of
1.0 +/- 0.2 deg, and a peak rate of ZHR = 30 +/- 7 meteors/hr, on top of the
annual shower activity.  This is identified not as the predicted narrow,
1-hr peak from the 1932 dust-trail encounter, but rather as the broad, 0.8-
degree-wide (1-day-wide) filament component that was predicted on CBET 1115
to peak at about Nov. 19.0 with a rate of ZHR = 40 meteors/hr (Jenniskens
2006, *Meteor Showers and Their Parent Comets*, Cambridge University Press,
p. 638).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2007 CBAT
2007 December 12                 (CBET 1166)              Daniel W. E. Green