Scientists have discovered about 200 variable stars that are located in the halo — scattered components of our Galaxy. The most distant of them is almost a million light-years away from us, that is, about half the way to the Andromeda galaxy.
The most distant stars of our Galaxy
Scientists from the University of Santa Cruz in California could find the most distant stars of our Galaxy. They are located in its halo. Usually this part of the Milky Way is not taken into account, describing it as a flat disk with a diameter of 100 thousand light-years.
It is here that the Solar System is located along with the Earth, but the bulk of the Galaxy falls on a halo — a spherical shell of a much larger diameter, in the center of which there is a well-known spiral structure.
It is very difficult to study the halo, because the stars are very rarely located here. Most of the masses of this region are formed by dark matter, which affects all processes in the Galaxy. But it was here that scientists were able to detect about 200 variable stars and estimate the distance to them.
How is it possible to determine the distance to the stars
It was possible to find new stars thanks to another study. The scientists worked on a program to study the galaxy cluster in Virgo. To do this, they used the Canadian-French-Hawaiian telescope (CFHT). In the course of their work, they were constantly faced with the fact that, in addition to galaxies, stars also got into the pictures.
Scientists became interested in them and it turned out that 208 luminaries belong to the variable types of the RR Lyrae. These ancient luminaries are interesting because they periodically contract and expand. Moreover, the frequency of such pulsations depends on the mass of the star.
Therefore, it is quite easy to determine the distance using variables of the RR Lyrae type. When scientists examined the stars observed together with the Virgo Cluster, they found that they were at distances exceeding the diameter of the galactic disk.
The most distant stars are a million light-years from the center of the Milky Way. This is about half the distance to the Andromeda galaxy, our nearest large neighbor. And this, in turn, indicates that there are actually no significant gaps of empty space between them.
According to https://phys.org
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