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(meteorobs) Meteorite temperatures.

    First, let me clear something up.  Dave English said I was a scientist.
I am in fact, an amateur astronomer that has specialized in meteor studies,
in particular, meteor spectroscopy for about 45 years.  When this discussion
came up several months ago I discussed this with two prominent meteor
scientists, Dr. Ian Halliday and Dr. Jiri Borovicka.  Dr. Halliday was in
charge of the MORP network that was set up across the Canadian Prairie
Provinces.  He said that there is no evidence of a normal sized meteorite
ever starting a fire.  He was of the opinion that meteorites could be warm
or cold at impact.  It depended on the trajectory and velocity among other
factors at re-entry.  He mentioned that the late Dr. Peter M. Millman
investigated the Benton N.B. fall.  This meteorite was recovered on the land
of a farmer almost immediately after the fall.  He said it was like a "hot
potato", too hot to hold comfortably in your hand, but you could toss it
from one hand to the other.  Not hot enough to scorch anything!  Other
meteorites have been cold at impact according to reports. Frost on a
meteorite is probably an "old wives tale", also! Unfortunately, as far as we
know, no meteorite has dropped into the backyard of a scientist that
immediately took the temperature of the object so hard evidence one way or
the other is lacking.  I discussed the end point height of fireballs with
both Halliday and Borovicka.  To my surprise, some fireballs have been
observed to lower altitudes than I expected.  The Abee meteorite was
observed as a red glow down to about 1.6 km above sea level.  We also
discussed the "near earth" temperature of meteorites.  It all depends
whether they are in sun light or on the dark side and for how long. Also
their albedo and type, stone or iron. Halliday referred me to a paper in
Meteoritics, volume 3, 1966 pages 59-70.  Paper, "Temperatures of Meteoroids
in Space" by Clay P. Butler of the U.S. Naval Radiological Defence Lab in
San Francisco.  If you are interested in this topic I suggest you look it
up.
    The moderator of this newsgroup asked us to minimize the discussion of
meteorites on meteorobs as this group has more to do with the astronomical
aspects of meteors rather than meteorites.  He suggested this discussion be
moved to the meteorite-list.
I respect his wishes and this is my last comment on this topic.  Much of the
past discussion on this topic can probably be found in the meteorobs
archives.
    I would also like to thank Dr Halliday and Dr Borovicka for their
comments.

Ed Majden

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