[meteorite-list] Carancas paper

[ohtsuka at jb3.so-net.ne.jp]

Hello list members, 

I have just downloaded a free PDF file of the letter paper on the Carancas event,  
published in A&A yesterday. This seems to be very interesting and the 
link is below: 

http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/abs/2008/26/aa09905-08/aa09905-08.html

Katsu
Tokyo, JAPAN

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A&A 485, L1-L4 (2008) 
DOI: 10.1051/0004-6361:200809905


Letter
The Carancas meteorite impact - Encounter with a monolithic meteoroid
J. Borovicka and P. Spurn? 

Astronomical Institute of the Academy of Sciences, Fricova 298, 25165 Ondrejov Observatory, Czech Republic 
    e-mail: borovic at asu.cas.cz 

Received 4 April 2008 / Accepted 4 May 2008

Abstract 
The formation of a 13-m wide impact crater by a stony meteorite near Carancas, Peru, on September 15, 2007 was an unexpected event. Stony meteoroids usually disintegrate in the atmosphere in many pieces, each landing at low velocity. We present examples of well-observed fireballs, which have all experienced atmospheric fragmentation. Using a simple model, we find that the Carancas meteoroid may have avoided fragmentation, if its strength was 20-40 MPa; such a strength would be comparable to the tensile strength of stony meteorites, but is higher than the strength of other observed meteoroids. We conclude that Carancas was a rare example of a monolithic meteoroid that was free of internal cracks. This example demonstrates that meteoroid strength can vary significantly from case to case and does not depend on meteoroid size. We estimate that the initial size of Carancas meteoroid was 0.9-1.7 m. Our model predicts an impact velocity that w
as in the range 2-4 km s-1. 


Key words: meteors, meteoroids -- Earth