(meteorobs) Re: Question re: 2006 Orionids

[Roberto G.]

From: "Bruce McCurdy" <bmccurdy at telusplanet.net>

CUT

>    Thanks Jeremie, that's certainly part of the question. The broader
> question is whether the enriched rates -- in both peak and duration -- of
> Orionids in 2006 can be attributed to a known physical process, even if it
> can't be specifically dated. Would this apparent clumping of meteoroids
> have been the result of a single outburst, where a filament has broadened
> out over the centuries without being fully dispersed? Could there possibly
> be gravitational factors at play?
>
>    I also wonder if there any useful analogies to be drawn between
> meteoroid streams and ring systems of giant planets. In particular I am
> thinking of the clumping found by Voyager 2 in Neptune's outermost ring
> (thought to be caused by resonances with an eccentric shepherd moon, so
> any analogy is likely to be imperfect). More recently, the Cassini probe
> has imaged fine structure in Saturn's E ring which is fed by the geysers
> of Enceladus. When examining the image at the below link, I found myself
> visualizing the relationship between a parent comet and its
> evolved-but-still-evolving meteoroid stream.
>
> http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2276
>
>    Naive questions to be sure, but I would be very interested to hear
> expert opinions.
>
>    Bruce

We must reminder as a meteor shower born:

a) asteroid case: an impact with a more little body shock the asteroid
    and many fragments are dispersed in the space, many are in orbit
    around the asteroid as a cloud, the gravitational forces of the planets
    after a time, little or long,  force they to fall on the asteroid or to 
be
    dispersed in the space, BUT the word dispersed must to be well
    understand: dispersed along the same orbit of the parent asteroid,
    with only very little differences on the orbital elements, during
    astronomical time (1,000 years-10,000years-100,000 years and more)
    the gravitational forces work on this differences and modify their 
orbits
    in a greatest mode, sometime very different from originals;

b) comet case: too in this case to can occur an impact but it's not
    necessary, the sublimation of the volatil elements disperse on the
    space meteoritical dusts, in general with a ratio it's of 1/100
    (1% of dust), the comets are in general littlest of asteroids then
    it's not possible that dusts go in orbit around a comet, too because
    there is the coma and the trail:

Now we have in the two cases (asteroids and comets) a clumps
spherical or as a disk, probably a the real form it's between the
two, with the time this disk/sphere take a elongated form
each time more, and do a part of a torus, then with many time
a complet torus: but the comets change their orbit
under NGF and gravitational forces then if a comet it's not
destroied, we can have many torus from a comet, and probably
this torus are deplaced a little each from others, then it's very
hard to known from which orbit come a torus, we can said
better from which epoch come a torus (the orbits of a specific
century), sometime the orbits change drammatically from a
orbit to the following, then if we not see with our eyes this
change we never known what occured.
Sometime occur too that for gravitational resonces in a
torus there are one or more dense clumps, this occur for
exemple with the Taurids and other known showers,
with the Leonid for exemple we have a very dense
clump near the comet and a very thin torus.
A decisive factor for to see a meteor shower it's
the period, if the period it's very short we shall
have (in general) a ZHR similar in the years, if the
period it's more of 100 years we can have as
for the Perseids some maximums around the
passage at perielium of the comet then a until
the next perielium each year minus meteors
(for the Perseid we shall have ZHR around 50-60
during the aphelium of the comet).
Sorry for the bad English and the long text.
Best greetings.
Roberto Gorelli