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(meteorobs) Re: [IMO-News] Excerpts from "CCNet 29/2001 - 23 February 2001"
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Clear skies,
Lew Gramer <owner-meteorobs@jovian.com>
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From: esko.lyytinen@minedu.fi
Date: Wed, 28 Feb 2001 11:40:24 +0200
Subject: RE:[IMO-News] Excerpts from "CCNet 29/2001 - 23 February 2001"
>...
>Also note the exciting reference from Dr. Fred Singer on his long-
>ago published predictions, regarding electrostatic dust transport
>in the region of small bodies. I wonder to what extent these will
>also be a significant factor for the much more complex comae which
>surround active comet nuclei? If so, then that effect should also
>have an important role in dust ejection models. Perhaps Rob, Peter
>and/or Esko would care to comment on whether they already account
>for this effect in their respective dust stream models?
No, such an effect is not accounted (explicitly) in the model (by Tom Van
Flandern and myself). There has been, in my mind, only vague thoughts on
the possible effects by electric forces on the particle spread. The effect
(if it proves to be real) may already have some effect on the empirical
properties of the model, as cross-sectional distributions of young trails
and on the density of particles in the trails with a given original delta_a.
>...
>Since the ratio of electrostatic to gravity force depends strongly on size
>of the dust particle, there will be a strong fractionation effect.
Particles
>in a certain size interval will be able to hop over large distances before
>returning to the surface. The tiniest particles will escape.
>...
According to this, the effect may have some effect on the number of certain
size ("The tiniest ...") meteoroids in the trails. I don't know yet, what
size this refers to. These may be too small for visual meteor phenomena, but
might have some importance on the threat to satellites for example when the
1-rev. trail passes most near to the Earth in 2005 (at about 0.0006 au)
containing most propably practically no particles big enough to produce
visual meteors (because of a big original delta_a with respect to the parent
comet). This trail near the encounter may however have a high particle
density of small (about 0.1 mm diameter) particles. As far as I know, there
is no observational data to predict this density.
Esko Lyytinen
http://www.egroups.com/list/imo-news
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