A number of series of orbits are obtained for the Large and Small Magellanic Clouds (LMC and SMC) revolving around a model Galaxy with a constant rotation velocity of 250 km s−1. A total mass within 50 kpc of the center of the Galaxy is 7×1011 M◉. We find several binary orbits of the LMC and SMC to be bound gravitationally throughout the past 1010 yr, if the perigalactic distance of the LMC is equal to or greater than 40 kpc. Approximately 600 test particles are distributed so as to simulate the hydrogen gas within the LMC and SMC. The tidal interaction among the triple system is numerically followed with these particles. We can reproduce the main characteristics of the Magellanic Stream, i.e., a narrow band of hydrogen gas emerges from the SMC and lies on a great circle of the sky passing the south galactic pole and the present position of the Clouds System and the radial velocity of the hydrogen gas is of the order of — 200 km s−1 at the tip of the Stream, if the following dynamically permissible parameters are assumed: (a) the orbital plane of the LMC is perpendicular to the galactic plane, (b) the perigalactic distance of the LMC is 50 kpc, (c) the sense of the revolution around the Galaxy is counterclockwise as seen from the present position of the sun, and (d) the SMC approached the LMC as close as 3 kpc from its center about 200 Myr ago. The distance of the model stream is in the range of 30 to 60 kpc measured from the sun. The total hydrogen mass of the Stream is, therefore, 108M◉ or slightly less. The close encounter is realized between the LMC and SMC in their binary orbits; this could be applied to understanding the magnetic lines of force as observed predominantly along the LMC–SMC line.
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Murai et al. (1980) studied this question.