[Prev][Next][Index][Thread]
(meteorobs) FWD from Keith Evanson
To: meteorobs@latrade.com
From: "Keith C. Evanson" <kevanson@slate.Minesdot edu>
Subject: Meteor heat transfer coefficients?
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Keith>>I have heard it said that a meteor's journey through the atmosphere
is
akin to a metallurgical refining process. The resultant meteorite is
supposedly a crudely-refined material with an iron base. <<
George>>Keith, I think the only parts of a meteorite that may go thru any
significant heating as it passed thru the atmosphere, would be found only
on the outside edges...or the crust. While a glowing meteor, the object
would be quite cold inside I would think? Therefore I don't think the
internal structure would be changed much if any? The raw materials would
still be intact. George Zay<<
George, without having any real meteor experience I can still comment based
on some fundamentals of physical science. We all know that NASA reentry of
various vehicles including the space shuttle is only possible because of
highly insulating refractories (ceramics) that are adhered to the vehicle
surface. The heat transfer coefficients of metals are far too great and
without the refractory tiles, the contents of the vehicle (including
people) would become extremely hot. If meteors are largely metallic or at
least similiar to iron ore, then the heat transfer coefficeints would
insure that heat IS transferred to the meteor interior rather rapidly. I
imagine that the friction between the meteor and the atmosphere raises the
temperature of the surface meteor material to a level that it is melting
and fluxing off. Is this fluxing responsible for the "tails" that we see
on many meteors? Does anyone know where I can find any actual physical
data regarding the compositions and/or heat transfer coefficients of
meteorites? How about information regarding the temperatures that meteors
experience during their flight?
Thanks alot, Keith.