Fig. 4: Effects of M33 and the LMC on the trajectory of the MW. | Nature Astronomy

Fig. 4: Effects of M33 and the LMC on the trajectory of the MW.

From: No certainty of a Milky Way–Andromeda collision

Fig. 4

As in Figs. 1 and 5, panels in the top row are projected in the orbital plane defined by the initial MW and M31 positions and velocities, whereas those in the bottom row are projected perpendicular to this orbital plane. Arrows point towards the initial position of M31. On the left, we compare MW trajectories in the two-body MW-M31 system to those in the three-body MW-M31-M33 system. In the centre and right, we show the orbit of the LMC and that of the MW before (centre) and after (right) the merger with the LMC in the MW-M31-LMC system. Compared to the two-body orbit, the inclusion of M33 reduces the transverse velocity of the MW relative to M31 and introduces only a small velocity perpendicular to the MW-M31 orbital plane. By contrast, the LMC increases the MW-M31 transverse velocity and causes a larger velocity perpendicular to the MW-M31 orbital plane.

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