A lot of stars in the Milky Way are gravitationally bound. This suggests they will spend their whole life in the Milky Way. They can speed around the galaxy, orbiting the galactic center like our Sun, however they do not move quick enough to ever escape from the gravitational pull of the galaxy. Some stars do have adequate speed to leave. They are referred to as runaway stars, or hypervelocity stars. Either through a close encounter with a great void, or perhaps a supernova, they have acquired significant speed, and are on their method to leave the Milky Way. For this most current study, hypervelocity stars often have a path that takes them away from the galactic plane. So we can study how dark matter impacts them to map dark matter in our galaxy.
We believe dark matter surrounds the Milky Way in a halo. Credit: L Jaramillo and O Macias, Virginia Tech
There is a catch. The speed of each hypervelocity star depends mostly on the interaction that provided a kick. We cant just look at a star and say the much faster its moving the less dark matter is nearby. Rather, the group took a look at the distribution of hypervelocity speeds and directions to provide a statistical view of dark matter. If * statistically * hypervelocity stars tend to move more gradually in a particular instructions, that can inform us about the distribution of dark matter.
There are only a couple dozen known hypervelocity stars, which isnt adequate to make an excellent dark matter map. The group produced a simulated sample of hypervelocity stars based on whether dark matter surrounds the Milky Way in a sphere, a flattened ellipsoid, and other shapes.
Hypervelocity stars arent the only tool we need to map dark matter in the galaxy, however as this study shows they can be an effective tool. It provides us further inspiration to find and track these speeding stars. They might just have one more lesson to teach us prior to they leave the Milky Way forever.
Referral: Gallo, Arianna, et al. “Probing the shape of the Milky Way dark matter halo with hypervelocity stars: a brand-new method.” arXiv preprint arXiv:2111.09657 (2021 ).
Like this: Like Loading …
To map dark matter in the Milky Way, we rely mostly on the movements of stars in our galaxy. Given that dark matter draws in routine matter gravitationally, the approach works well for locations of the galaxy where there are stars. A current research study proposes a way to map more of our galaxys dark matter using runaway stars.
We can study how dark matter affects them to map dark matter in our galaxy.
Hypervelocity stars arent the only tool we have to map dark matter in the galaxy, however as this study reveals they can be a powerful tool.
To map dark matter in the Milky Way, we rely primarily on the motions of stars in our galaxy. Because dark matter attracts routine matter gravitationally, the approach works well for areas of the galaxy where there are stars. A current research study proposes a way to map more of our galaxys dark matter using runaway stars.
