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Re: (meteorobs) Tunguska bolide & Beta taurid stream
Jure,
You make a lot of good points. It should be noted that many other authors
have discussed these points and Kresak and Sekanina were just two of the
main players.
Defunct comets, as the Geminid parent "asteroid" Phaethon is assumed to be,
are probably quite common, and Duncan Steel, David Asher and others have
argued in great detail that there is a excess of asteroids in orbits
similar to P/Encke. The excess they assume to be defunct cometary
fragments of Encke or its precursor.
Regarding meteors exploding high in the atmosphere and asteroids low in
the atmosphere, there is no comparison due to the huge difference in
atmospheric pressure between these regions. It has been well demonstrated
by the European fireball network, that assumed cometary objects
disintegrate in a series of flares when still at high altitude, whereas
assumed rocky bodies survive with little of no flaring to much lower in
the atmosphere. Despite this, these rocky bodies (and some of these are
recovered meteorites) still break up at much lower pressures than the
tensile strength of the recovered meteorite would suggest. This would
indicate the body had pre-existing fractures presumably from its creation
in a collision.
Cheers, Rob
Robert H. McNaught
rmn@aaocbn.aaodot gov.au
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