Jonathan D. Diaz, Kenji Bekki
We present an N-body model that reproduces the morphology and kinematics of
the Magellanic Stream (MS), a vast neutral hydrogen (HI) structure that trails
behind the Large and Small Magellanic Clouds (LMC and SMC, respectively) in
their orbit about the Milky Way. After investigating $8\times10^6$ possible
orbits consistent with the latest proper motions, we adopt an orbital history
in which the LMC and SMC have only recently become a strongly interacting
binary pair. We find that their first close encounter 2 Gyr ago provides the
necessary tidal forces to disrupt the disk of the SMC and thereby create the
MS. The model also reproduces the on-sky bifurcation of the two filaments of
the MS, and we suggest that a bound association with the Milky Way is required
to reproduce the bifurcation. Additional HI structures are created during the
tidal evolution of the SMC disk, including the Magellanic Bridge, the
"Counter-Bridge", and two branches of leading material. Insights into the
chemical evolution of the LMC are also provided, as a substantial fraction of
the material stripped away from the SMC is engulfed by the LMC. Lastly we
compare three different N-body realizations of the stellar component of the
SMC, which we model as a pressure-supported spheroid motivated by recent
kinematical observations. We find that an extended spheroid is better able to
explain the stellar periphery of the SMC, and the tidal evolution of the
spheroid may imply the existence of a stellar stream akin to the gaseous MS.
View original:
http://arxiv.org/abs/1112.6191
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