Lost Intergalactic Stars: A Baffling Hubble View

Among large clusters of galaxies, gravitationally unbound stars “emitted from a ghostly veil of light” have been “wandering like lost souls” for billions of years. This is how the research team now describes the result of an analysis using the Hubble Space Telescope. The discovery cannot be explained by current theories about the formation of these stars, because they apparently separated from them or were expelled in collisions that were not delayed after the formation of galaxies. Somehow, co-author James G. of Yonsei University in Seoul says that single stars formed in large numbers in the early universe.

formed with galaxies

As the research team explainsThe work examined 10 galaxy clusters as far as 10 billion light-years away. The light that originates between the respective galaxies, that is, from the displaced stars, was measured. Because the light is so weak, measurements were only possible from space. Emitted by the recesses of galaxy clusters, the light from these stars has been shown to remain constant no matter how far into the past you look. This means that the stars were already homeless when the clusters formed.

It is not known how the intergalactic stars arrived, explains study leader Hyungjin Joo. Until now it was thought that they form when galaxies move through regions rich in gas and lead to the formation of stars there. Some of these new stars will then be slowly ejected from the galaxy. But then, as the universe got older, it had to become more. The same is true when stars lose their homes in a giant galactic collision. This finding contradicts both scenarios.

Hyungjin Joo adds that if you can learn more about how they formed, you can learn something about the formation of the galaxy clusters themselves. In addition, displaced stars could help learn more about the nature of dark matter that has been described only theoretically so far. Research work It was published in the journal Nature.

(mo)