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(meteorobs) Re: Cepheus Meteor Activity Dec 5?



George Zay wrote:

> I was informed by an individual who resides in Tulsa, Oklahoma, USA of
meteor
> activity apparently radiating from the general area of Cepheus. It
occurred on
> the early evening of Dec 5/6 at about 0h00 UT(18h00 CST). Sighted were 11
> meteors with a 2-3 minute period. The meteor's had an apparent medium
> velocity. Magnitudes were relatively bright...+2 and +1 range. The
individual
> who made this report is not an experienced meteor observer, but is
astronomy
> savvy. Despite this fact, a minor shower is possible and future
observations
> around this date may prove fruitful? 

I found it useful to give an estimate of the upper velocity limit of a
potential meteor shower. I assumed a radiant position at alpha=335deg,
delta=+65deg, directly within the box of Cepheus. This position has a
distance of 108deg from the apex of the Earth's motion. The further the
radiant distance from the apex, the smaller the geocentric velocity. If I
assume 42km/s as the maximum heliocentric velocity of any solar-bound
particle, I get 21.5km/s geocentric velocity -- and 24km/s maximum entry
velocity into the Earth's atmosphere. Since the radiant was high in the
sky, the meteors should give about the same picture like the kappa-Cygnid
meteors. The radiant was roughly 60deg above the horizon, the fastest
meteors should then appear in Pegasus with about 10deg/s speed. So all
meteors should be a the low end of the velocity range. The velocity
impression of the guy cited is certainly not accurate; nevertheless, I wish
to show how such calculations may help judge whether or not a suspect
radiant is real.

Rainer Arlt
---------------------------------
Visual Commission
International Meteor Organization
email:  visual@imodot net
Homepage:  http://www.imodot net
---------------------------------