36th DPS Meeting, 8-12 November 2004
Session 34 Comets: Nuclei, Tails, Solar Wind
Poster II, Thursday, November 11, 2004, 4:15-7:00pm, Exhibition Hall 1A

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[34.14] Dynamical Zodiacal Cloud Models Constrained by High Resolution Spectroscopy of the Zodiacal Light.

S.I. Ipatov (Catholic University of America, Washington, DC, USA), A.S. Kutyrev (NASA/GSFC, Greenbelt, MD, USA), G.J. Madsen (University of Wisconsin-Madison, Madison, WI, USA), J.C. Mather, S.H. Moseley (NASA/GSFC, Greenbelt, MD, USA), R.J. Reynolds (University of Wisconsin-Madison, Madison, WI, USA)

We have developed a set of self-consistent dynamical models of the Zodiacal cloud, following the orbital evolution of dust particles under the gravitational influence of planets, radiation pressure, Poynting-Robertson drag, and solar wind drag (Ipatov et al., Annals of New York Academy of Sciences, 2004, v. 1017, 66-80). Three populations were considered, originating from the Kuiper belt, asteroids and comets. Using the models developed, we investigated how the solar spectrum is changed by scattering by the zodiacal cloud grains. For each particles population different scattering functions were considered.

Reynolds, Madsen and Moseley (ApJ, in press) have observed the Zodiacal light spectrum near the solar Mg I\lambda5184 absorption line. For the first time, high resolving power spectra (R=25,000) with high signal to noise ratio provide an opportunity to model the shape of the Fraunhofer line in the Zodiacal spectrum. The line profile depends on the velocity, size, density distribution of particles on the line of sight and their respective scattering properties. We have carried out an initial comparison of our models with the observed spectra. The value of the Doppler shift and the shape of the Fraunhofer line produced by our model is in general agreement with the observations. Unlike results by Clarke et al. (A&A, 1996, 308, 273), our modeled spectra do not exhibit strong asymmetry. Different particles populations produce clearly distinct model spectra of the Zodiacal light. At the same time, the results of modeling are relatively insensitive to the scattering function considered. We believe that with improved and more extensive observations it will be possible to distinguish the sources of dust and impose constraints on the particle size distribution. This should result in a self-consistent 3D model of Zodiacal cloud density and velocity particles distribution.

This work was supported by NASA (NAG5-12265) and the NSF through AST-0204973.

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