Cloud with Its Gravity. What Comes Next?
Universe Today | Scott Alan Johnston | 2023 Apr 23
Our galaxy’s largest nearby companion is the Large Magellanic Cloud (LMC), a dwarf galaxy visible to the naked eye in the Southern Hemisphere. In recent years, new theoretical research and better observational capabilities have taught astronomers a great deal about our (not-so-little) neighbour. It’s becoming increasingly clear that the LMC is helping shape the Milky Way’s evolution.Large Magellanic Cloud ~ Credit: ESO/VMC Survey
“It was long assumed that our galaxy lives a quiet life of a hermit, with the nearest ‘big’ neighbour being Andromeda some 800 kiloparsecs away,” says Eugene Vasiliev ... “But with the growing realization that the LMC is rather massive, and because of a peculiar ‘historical moment’ (it just passed near the pericentre of its orbit, where its velocity and the reciprocal effect it imparts on the Milky Way are highest), we can no longer ignore the perturbations to our Galaxy that it causes.”
Weighing in at 10-20% the mass of our own galaxy, the LMC is worth taking seriously. Astronomers believe that it’s on its first orbit around the Milky Way. Before that orbit began, it was a spiral galaxy in its own right. Interacting with the Milky Way distorted its spiral arms, though it still features a strong central bar as evidence of its previous structure.
The Milky Way, too, was changed by the interaction. The stars and stellar streams nearest to the LMC had their orbits deflected, for example, and there were larger, structural changes to the Milky Way too. Because the Milky Way isn’t rigid, but rather made up of stars, dust, gas, and rock in varying densities, parts of the galaxy closer to the LMC were affected more than distant parts. The end result was a subtle-but-significant deformation in the shape of the galaxy, especially in the outer regions. ...
The Effect of the LMC on the Milky Way System ~ Eugene Vasiliev
- Galaxies 11(2):59 (Apr 2023) DOI: 10.3390/galaxies11020059
- arXiv > astro-ph > arXiv:2304.09136 > 18 Apr 2023