ESA | Space Science | Science & Technology | Gaia | 2018 Sep 19
ESA’s star mapping mission, Gaia, has shown our Milky Way galaxy is still enduring the effects of a near collision that set millions of stars moving like ripples on a pond.
The close encounter likely took place sometime in the past 300–900 million years. It was discovered because of the pattern of movement it has given to stars in the Milky Way disc – one of the major components of our Galaxy.
The pattern was revealed because Gaia not only accurately measures the positions of more than a billion stars but also precisely measures their velocities on the plane of the sky. For a subset of a few million stars, Gaia provided an estimate of the full three-dimensional velocities, allowing a study of stellar motion using the combination of position and velocity, which is known as ‘phase space’.
In phase space, the stellar motions revealed an interesting and totally unexpected pattern when the star’s positions were plotted against their velocities. ...
Gaia Detects a Shake in the Milky Way
University of Barcelona | 2018 Sep 20
A Dynamically Young and Perturbed Milky Way Disk ~ T. Antoja et al
- Nature 561(7723):360 (20 Sep 2018) DOI: 10.1038/s41586-018-0510-7
arXiv.org > astro-ph > arXiv:1804.10196 > 26 Apr 2018