[meteorite-list] Nice meteor shower estimator

[mexicodoug]

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