[meteorite-list] Nice meteor shower estimator

From: mexicodoug <mexicodoug_at_meteoritecentral.com>
Date: Fri, 16 Nov 2007 16:39:40 -0600
Message-ID: <007c01c828a1$94342470$4001a8c0_at_MICASA>

Dear Listees, especially those staying up for the midnight crescendo of an
average Leonid meteor shower this Saturday evening - Sunday morning:

http://leonid.arc.nasa.gov/estimator.html
"Most visible Leonids are between 1 mm and 1 cm in diameter. For example, a
Leonid meteor of magnitude +5, which is barely visible with the naked eye in
a dark sky, is caused by a meteoroid of 0.5 mm in diameter and weights only
0.00006 gram."*

"Persistent train/Ursa Major on left" :
http://leonids.hq.nasa.gov/leonids/gallery/files/195.html

That is intended to be the threshold limit of visible Leonids, indicating
others can be much havier. Extrapolating this asumptions of the 0.00006
gram meteoroid, once can calculate that a -7 magnitude (minus seven = around
twice Venus) bright fireball would weigh in at 3 grams, though the high
speed of the Leonids makes it unlikely anything of that size could make it
to the ground without a major high altitude KA-BOOM. This agrees very
nicely with Beech M. and and L. Foschini, "Leonid electrophonic bursters",
A&A 367, 1056-1060 (2001), where it is mentioned that 100 gram fragments are
suspected to reside in the Leonid meteoroid stream. Their reference for
that defers to Bellot-Rubio, Ortiz and Sada (2000) and Spurney et. al
(2000). Yes, the same Ortiz that Brown-Ortiz tiff.
.
The average height of the end of the luminescent path of bright Leonids is
estimated at 80 km. So the gap is awefully large...

Best wishes,
Doug
Received on Fri 16 Nov 2007 05:39:40 PM PST