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**Session 19 - Solar & Planetary Systems.**

*Display session, Monday, January 13*

*Metropolitan Ballroom, *

## [19.05] Quasi-stationary States of Dust Flows Under Pointing-Robertson Drag: New Analytical Solutions

*N. Gor'kavyi (Crimean Obs.), L. Ozernoy (CSI/GMU and GSFC/NASA), J. Mather (GSFC/NASA), T. Taidakova (Crimean Obs.)*
The effect of solar/stellar radiation on dust particles trajectories
(the P-R drag) has been studied by a number of authors and applied to
interplanetary dust dynamics in numerical computations. Meanwhile some
important features of dust flows can be studied analytically by implementing
the continuity equation written in particle's orbital elements as
coordinates (Gor'kavyi, Ozernoy, amp; Mather 1997). By employing this approach
and integrating the continuity equation, we are able to find two integrals
of motion when the P-R drag dominates the dissipative forces in the dust
flow. In this case, the integrals of motion are C_1=ae^-4/5(1-e^2) and
C_2=ne^1/5\sqrt1-e^2. The integral C_1 that describes the trajectory
of the dust flow in the space of particle's orbital
elements, coincides with that for the motion of individual
particles (Wyatt amp; Whipple 1950), and the integral C_2 (which is a new
result) allows to determine the density of the flow along its trajectory.
Taken together,
C_1 and C_2 imply conservation of the particle's flux in the flow under
the P-R drag. These integrals of motion enable us to explore basic
characteristics of dust flows from any sources in the Solar system (such as
asteroids, comets, Kuiper belt, etc.) or in another planetary system. In
particular, we have reproduced the clasical solution n\propto 1/r that
represents approximately the overall distribution of dust in the Solar system.
We have also investigated the factors that could be responsible for
deviations of the power law index in n\propto r^-\alpha from \alpha=1:
non-uniform distribution of dust sources around the observer, eccentricity
of particle orbits,
and the change of particle's sizes due to evaporation. Comparison with the
measured dust distribution in the Solar system is done.

References:

Gor'kavyi, N., Ozernoy, L. amp; Mather, J. 1997, ApJ 474 No.1 (in
press)

Wyatt, S.P. amp; Whipple, F.L. 1950, ApJ 111, 134

**Program
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