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Session 19 - Solar & Planetary Systems.
Display session, Monday, January 13
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.
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 listing for Monday