[meteorite-list] Changes in radiants over time

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Tue, 3 Nov 2015 18:17:46 -0600
Message-ID: <600471.57212.bm_at_smtp115.sbc.mail.gq1.yahoo.com>

E.P., List,

Most of this is straight from
the Wikipedia; it's just the
basics, but they say it so well.
https://en.wikipedia.org/wiki/Meteor_shower#Radiant_point

Meteor "streams" are dust and
particles shed by comets and
strung out along the comet's
orbit. Some of these orbits
intersect the Earth's orbit.

Many showers have a radiant
point that changes position
during the interval when it
appears. For example, the
radiant point for the Delta
Aurigids drifts by more than
a degree per night.

The radiant also moves slightly
from night to night against the
background stars (radiant drift)
due to the Earth moving in its
orbit around the sun.

The gravitational pull of the
planets determines where the
dust trail would pass by Earth
orbit, but the same gravitational
effects perturbs the trails. Over
longer periods of time, the dust
trails can evolve in complicated
ways.

Both gravitational influences
and radiation pressure disperse
the meteoroids and creates much
broader streams.

The Taurids are particularly
complex in their radiant changes:
http://articles.adsabs.harvard.edu/full/seri/JIMO./0033//0000041.000.html

Over the very long term, meteor
streams precess just as the planets
do. The precession of the meteoroid
stream orbit caused by planetary
perturbations will also alter the
date on which a shower occurs.
http://www.math.nus.edu.sg/aslaksen/gem-projects/hm/0102-1-stonehenge/predic
ting_meteor_showers.htm

An interesting piece by Duncan
Steel on the association of Earth-
crossing asteroids with meteoroid
streams:
http://link.springer.com/article/10.1007%2FBF00671497#page-1

Sterling Webb
---------------------------------------------------
-----Original Message-----
From: Meteorite-list [mailto:meteorite-list-bounces at meteoritecentral.com] On
Behalf Of E.P. Grondine via Meteorite-list
Sent: Tuesday, November 03, 2015 9:56 AM
To: mpml at yahoogroups.com
Cc: meteorite-list at meteoritecentral.com
Subject: [meteorite-list] Changes in radiants over time

HI all -

This author, Bard Marsden, is claiming that the radiant of the Taurid Meteor
Stream has drifted over the millenia:

https://sites.google.com/site/fromthedeepoceanabove/

Based on the mythological evidence he has assembled, this may be likely, but
what would be the mechanics involved?

E.P.
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Received on Tue 03 Nov 2015 07:17:46 PM PST