Astronomers have discovered more than 200 distant pulsating variable stars of the RR Lyrae type in the stellar halo of the Milky
Scientists used data from a study of the clusterDestined to study the cluster of galaxies far beyond the Milky Way to learn more about our Galaxy. In the collected data, they found 208 RR Lyrae stars located in a stellar halo at a distance of 20 to 320 kiloparsecs from Earth (65 thousand to 1 million light years).
Illustration of the structure of the Milky Way. A giant stellar halo surrounds a relatively small stellar disk. Image: NASA, ESA, and A. Feild [STScI]
The stellar halo is the most massive componentMilky Way. It surrounds a stellar disk whose diameter is about 100,000 light years. There is a central bulge in the middle of the disk, and a surrounding halo that contains the oldest stars in the galaxy and extends for hundreds of thousands of light years in all directions.
Stars (in halo, approx.- "High-tech") are very rare compared to the high stellar density of the disk and bulge, but the halo is dominated by dark matter, and in fact it contains most of the mass of the galaxy.
Raja GuhaThakurta, professor of astronomy and astrophysics at the University of California at Santa Cruz, study co-author
Characteristic pulsations and brightness of RR type starsLyres make them excellent "standard candles" for measuring galactic distances. The sky is full of stars, some of them appear brighter, some appear dimmer. In this case, the apparent brightness can depend both on the properties of the star itself and on the distance to it.
Characteristic pulsation of RR Lyrae starsallows you to accurately determine the distance to them due to the known absolute magnitude, which is approximately the same for all stars of this type. The researchers used the data to trace the outer limits of the Milky Way's halo. According to GuhaThakurt, it turned out that "our galaxy and Andromeda are so large that there is almost no space between the two galaxies."
Read more:
The most beautiful photos of "Webb" for 2022: see what the $ 10 billion telescope did
The sun opened the year with a flash of the most powerful class
The secret of the durability of Roman concrete is revealed: it can be restored