The M31 Velocity Vector. III. Future Milky Way-M31-M33 Orbital Evolution, Merging, and Fate of the Sun

Abstract

We study the future orbital evolution and merging of the MW-M31-M33 system, using a combination of collisionless N-body simulations and semi-analytic orbit integrations. Monte-Carlo simulations are used to explore the consequences of varying the initial phase-space and mass parameters within their observational uncertainties. The observed M31 transverse velocity implies that the MW and M31 will merge t = 5.86 (+1.61-0.72) Gyr from now, after a first pericenter at t = 3.87 (+0.42-0.32) Gyr. M31 may (probability p=41%) make a direct hit with the MW (defined here as a first-pericenter distance less than 25 kpc). Most likely, the MW and M31 will merge first, with M33 settling onto an orbit around them. Alternatively, M33 may make a direct hit with the MW first (p=9%), or M33 may get ejected from the Local Group (p=7%). The MW-M31 merger remnant will resemble an elliptical galaxy. The Sun will most likely (p=85%) end up at larger radius from the center of the MW-M31 merger remnant than its current distance from the MW center, possibly further than 50 kpc (p=10%). The Sun may (p=20%) at some time in the next 10 Gyr find itself moving through M33 (within 10 kpc), but while dynamically still bound to the MW-M31 merger remnant. The arrival and possible collision of M31 (and possibly M33) with the MW is the next major cosmic event affecting the environment of our Sun and solar system that can be predicted with some certainty. (Abridged)

58 pages, 16 figures, to be published in ApJ. Version with high resolution figures and N-body movies available at http://www.stsci.edu/~marel/M31 . Press materials, graphics, and visualizations available at http://hubblesite.org/newscenter/archive/releases/2012/20

References in corpus (5)

• Are the Magellanic Clouds on their First Passage about the Milky Way?
• Are disk galaxies the progenitors of giant ellipticals?
• Bar imprints on the inner gas kinematics of M33
• Revisiting the Role of M31 in the Dynamical History of the Magellanic Clouds
• A Dynamical Model of the Local Group

Cited by in corpus (21)

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• Orbits of Massive Satellite Galaxies: I. A Close Look at the Large Magellanic Cloud and a New Orbital History for M33
• A dynamical model of the local cosmic expansion
• Galaxy Groups
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• Space Motions of the Dwarf Spheroidal Galaxies Draco and Sculptor based on HST Proper Motions with ~10-year Time Baseline
• Dynamics of astrophysical objects against the cosmological background
• Solo dwarfs III: Exploring the orbital origins of isolated Local Group galaxies with Gaia Data Release 2
• The Local Group in the cosmic web
• Resequencing the Hubble sequence and the quadratic (black hole mass)-(spheroid stellar mass) relation for elliptical galaxies
• The M31/M33 tidal interaction: A hydrodynamic simulation of the extended gas distribution
• Dwarfs in the Milky Way halo outer rim: first in-fall or backsplash satellites?
• The orbital evolution of UFDs and GCs in an evolving Galactic potential
• Comparative analysis of the influence of Sgr A* and nearby active galactic nuclei on the mass loss of known exoplanets
• Future merger of the Milky Way with the Andromeda galaxy and the fate of their supermassive black holes
• A Differential RR Lyrae Line-of-Sight Distance Between M31 and M33
• The outskirts of M33: Tidally induced distortions versus signatures of gas accretion
• Local Group Proper Motion Dynamics
• Revisiting the Proper Motions of M31 and M33 Using Massive Supergiant Stars with Gaia DR3