A third of the stars of the Milky Way leave their birthplace

Map of Star Migration

Astronomers from the University of New Mexico, together with other scientists from the Sloan Digital Sky Survey project ( SDSS , Sloan Digital Sky Survey), built a new map of the Milky Way showing star migration routes. Published on July 29 in The Astrophysical Journal, the work reveals new information about how stars are born and how they travel throughout their lives.

Many people change their place of residence and move to new places, sometimes located quite far from the place of birth. Scientists have found that about 30% of the stars also significantly move away from the places where they were born.

As part of the SDSS survey, the APOGEE spectrograph (Apache Point Observatory Galactic Evolution Experiment) also works, with which scientists, using high-resolution infrared spectroscopy, observe the inner regions of the galaxy hidden by cosmic dust. Using APOGEE, scientists are exploring about 100 thousand red giants - not only their spectral characteristics, but also their migration habits, and through them the history of the entire Milky Way galaxy.

Spectral analysis tells in detail about the structure of stars. At the same time, the previous stars, having synthesized chemical elements in their bowels, after death transfer these elements to form new stars - thus, one can judge their origin by the composition of the stars.

Since the process of such “chemical enrichment” is proceeding at different rates in different regions of the galaxy, the average number of heavier elements in stars varies for different regions. By accurately determining the composition of a star, astronomers can very likely predict in which region it formed.

Choosing 15 heavy elements as markers, the scientists made calculations based on the data on the composition of stars obtained over six years of observations, and were surprised to find that about 30% of the stars formed far enough from where they were at the time of their study.

According to the results of the study, the migration of stars occurs mainly in radial directions - either to the center of the galaxy, or from it. Most likely, this behavior is explained by the unevenness of the galactic disk, in which there are pronounced sleeves and empty spaces. Migration of stars has previously been observed, but only in neighboring ones with our Sun. Now we can judge that this process is observed throughout the galaxy.