Constraining the orbital history of the Magellanic Clouds: A new bound
  scenario suggested by the tidal origin of the Magellanic Stream
  Bound orbits have traditionally been assigned to the Large and Small
Magellanic Clouds (LMC and SMC, respectively) in order to provide a formation
scenario for the Magellanic Stream (MS) and its Leading Arm (LA), two prominent
neutral hydrogen (HI) features connected to the LMC and SMC. However, Hubble
Space Telescope (HST) measurements of the proper motions of the LMC and SMC
have challenged the plausibility of bound orbits, causing the origin of the MS
to re-emerge as a contested issue. We present a new tidal model in which
structures resembling the bifurcated MS and elongated LA are able to form in a
bound orbit consistent with the HST proper motions. The LMC and SMC have
remained bound to each other only recently in our model despite being
separately bound to the Milky Way for more than 5 Gyr. We find that the MS and
LA are able to form as a consequence of LMC-dominated tidal stripping during
the recent dynamical coupling of the LMC and SMC. Our orbital model depends on
our assumption that the Milky Way has a constant circular velocity of V_cir=250
km/s up to 160 kpc, which implies a massive isothermal halo that is not
completely rejected by observations.
