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Re: (meteorobs) Chi Orionid Shower 12/1999

Hi!

I wasn't really active during the first half of December, so I can't
really tell, but there appears to have been no Chi Orionid outburst.
I am 100% sure that the fireball you saw was no Leonid. There are several
reasons. First - the activity ends by November 23. The Leonid stream is
quite compact and the Earth doesn't encounter it anymore in December.
Second - these are cometary meteoroids of very high velocities, combine
the two factors and there is no way it would leave a meteorite. Cometary
meteoroids are like snowlakes (almost) - they cannot withstand the
immense pressures of atmospheric entry. They are destroyed very high up
in the atmosphere, around 100 km or so. Third - they are destroyed
(ablated actually...) so high up in the atmosphere that they do not
produce window-shattering sonic booms, they produce no sonic booms at all
as the air at that height is too thin (not dense enough actually...) to
carry sound effectively. So a Leonid is out of question.
   The odds for this fireball being a Chi Orionid are somewhat better.
Chi Orionids are a continuation of the Taurids, so I suppose the
meteoroids are comparable and so are the characteristics of the meteors.
Ecliptic meteor showers, Taurids in particular, are known for their
bright fireballs! They often produce sonic booms. But these too (I
think...) are of cometary origin and they would not produce a meteorite.
   If you heard an explosion-like sound, I'd say it was a sonic boom,
since the fireball, if it had some length (here we go again...) would
leave the meteorite somewhere else. I'd say you heard a sonic boom. If it
indeed dropped a meteorite, then there's probably no doubt that it was a
sporadic.

No expert, but I hope this helps...

Clear skies!

Jure A.

CHE3002 wrote:

> Hello,
> Did anyone notice any enhanced activity in the Chi Orionids of last
> year?
> I live in S.E Ireland and saw a gigantic fireball whose path
> intersects the Chi Orionid radiant. The fireball eventually landed in
> my area, but as yet remains undiscovered. Several houses had
> their windows shattered when the fireball landed.
> A friend of mine argues that it was probably a late member of the
> Leonid storm.
> Did anyone else notice an increase in Chi Orionid activity in
> December of last year?
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