Astronomers have discovered the most distant stars in our Galaxy halfway to Andromeda

(ORDO NEWS) — From the Milky Way to the Andromeda galaxy, even at the speed of light, it will take more than two and a half million years. However, the most distant stars in our Galaxy have overcome at least half of this path.

The Milky Way consists of two main components: the visible galactic disk (which is visible in the night sky as a dense band of stars) and the invisible galactic halo, which has a spherical shape and extends far beyond the galactic disk.

The halo is mostly made up of gas, dark matter , and rare stars that are not easy to detect.

However, as reported on the official website of the University of California at Santa Cruz (USA), astronomers were able to identify almost 200 such stars, known as “RR Lyrae variables”.

These are relatively old low-mass stars with almost the same luminosity, which scientists use as standard candles to determine distances in the universe.

The diameter of the galactic disk of the Milky Way is about 100 thousand light years, but the most distant star of its galactic halo was found at a distance of more than a million light years from Earth, that is, almost halfway to the Andromeda galaxy, our closest large neighbor.

Given that Andromeda is larger than the Milky Way, it is possible that its galactic halo is no less extensive. In other words, two large galaxies literally “push their elbows” in outer space.

Curiously, this discovery was a “by-product” of another study aimed at studying the Virgo Cluster – a group of galaxies closest to our Local Group, which includes the Milky Way and the Andromeda galaxy.

While studying the giant elliptical galaxy M 87, the researchers unwittingly fixed the stars located between it and the Earth, thanks to which they discovered RR Lyrae variables, whose main feature is the habit of regularly expanding and contracting in a repeating cycle.

Astronomers have discovered the most distant stars in our Galaxy halfway to Andromeda
RR Lyra’s star is the brightest in its class

Thus, American astronomers were able to confirm the theoretical calculations of the diameter of the galactic halo and clarify the picture of how neighboring galaxies are located within the Local Group.

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