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		| Paper: | 
		Comparing Gaseous and Stellar Orbits in a Spiral Potential | 
	 
	
		| Volume: | 
		480, Structure and Dynamics of Disk Galaxies | 
	 
	
		| Page: | 
		141 | 
	 
	
		| Authors: | 
		Gómez, G. C.; Pichardo, B.; Martos, M. A. | 
	 
	
	
		| Abstract: | 
		It is generally assumed that gas in a galactic disk follows closely non
 self-intersecting periodic stellar orbits. In order to test this common
 assumption, we have performed MHD simulations of a galactic-like disk under the
 influence of a spiral galactic potential. We also have calculated the actual
 orbit of a gas parcel and compared it to stable periodic stellar orbits in the
 same galactic potential and position. We found that the gaseous orbits approach
 periodic stellar orbits far from the major orbital resonances only. Gas orbits
 initialized at a given galactocentric distance but at different azimuths can be
 different, and scattering is conspicuous at certain galactocentric radii. Also,
 in contrast to the stellar behavior, near the 4:1 (or higher order) resonance
 the gas follows nearly circular orbits, with much shorter radial excursions than
 the stars. Also, since the gas does not settle into a steady state, the gaseous
 orbits do not necessarily close on themselves. | 
	 
	
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