What happens if a star finds itself inside a dense cloud of dark matter? The authors of the new study believe that evolution can go backwards. After modeling the evolution of such a stellar population, scientists identified a new “main dark sequence.” The most surprising thing is that their hypotheses can be confirmed; You just need to look closely at the center of the Milky Way.

According to conventional models, stars cannot form within 0.3 light-years (0.1 parsecs) of the Milky Way’s supermassive black hole, called S-stars. For this reason, they migrated to this region after they were born. The problem is their age, they are 15 million years younger. Additionally, their spectra have characteristics of more mature stars. It is also unusual to find so many massive stars among S-stars. At the same time, there are very few adult stars on the outskirts of the Galactic center.

Despite unsuccessful attempts to find dark matter in the disk of the Milky Way and other similar galaxies, some astronomers suggest it is still there. Moreover, according to their calculations, the density at the center of the Galaxy should be high enough to affect the internal processes of stars.

Authors of new works published in open access on the site arXiv, described for the first time what a stellar population “influenced” by dark matter would look like. They modeled the evolution of such objects using results from previous studies. Based on the results, scientists created a diagram of the new “dark main sequence.”

Stars develop according to known scenarios. They are stable as long as the inward force of gravity is balanced by the outward energy from nucleosynthesis. Their brightness, temperature and radius are related to each other. This is reflected in the famous Hertzsprung-Russell diagram. Meanwhile, in the young universe and in regions with high dark matter density, the annihilation of this matter could be an important source of additional energy.

In the new study, scientists modeled the evolution of two populations of stars ranging in mass from 1 to 10 solar masses, evolving without dark matter and with the participation of dark matter. The influence of dark matter was already taken into account after the formation of the body, when this “ready” star was in a hypothetical cloud of dark matter on the outskirts of the center of the Galaxy.

Researchers from the Oskar Klein Center for Cosmic Particle Physics (Sweden) and the Kavli Institute for Particle Astrophysics and Cosmology (USA) have derived four scenarios for the evolution of stars under the influence of dark matter. In the first group, the destruction of dark matter replaces only part of the nucleosynthesis. Hydrogens are processed more slowly, development slows down. Their lifetimes can be tens to hundreds of times longer than those of “ordinary” stars.

The second group is “stuck” on Xenia’s evolutionary path due to the diversity of dark matter that enters them. Ordinary stars quickly pass this path: they contract, “ignite” nucleosynthesis within themselves and enter the main sequence. In the presence of large amounts of dark matter, even stars that have entered the main sequence can quench their nucleosynthesis enough to revert to the Henia pathway. Theoretically, such stars should live for very long periods of time, but the study’s authors only modeled 10 billion years.

The third group is “stuck” in the Hayashi evolution path, where there are stars in which nucleosynthesis has not yet begun. Ordinary stars leave it on the path to Xenia or turn into brown dwarfs. The destruction of dark matter in these stars completely replaces nucleosynthesis, and the luminaries enter the Xenia pathway without “burning hydrogen.” Such stars appear young but have the characteristics of old stars that “survived” nucleosynthesis. They are immortal.

Finally, the dark matter of stars in the fourth group “reverses” evolution. Maybe we can even turn them into gas clouds. On the outskirts of the center of the Milky Way there are similar objects called G-objects, which resemble dense nuclei surrounded by a cloud of gas.

In the diagram of such stars – the “dark main sequence”, as the authors call it – three features are visible. The first is the presence of a large number of massive stars in the main sequence, since all low-mass stars change their evolutionary trajectories due to the more pronounced influence of dark matter on them. Secondly, Hayashi’s track has a lot of stars because they are “immortal”. Third, there are many huge lights on the Henyi track. In general, this hypothesis describes well some properties of known cosmic bodies near the center of the Galaxy.

These assumptions can be verified using detailed observations of objects near the galactic center. It is possible that many of the stars identified were sorted out during the observations. For example, the lights at the Hayashi track can be quite cold and unsampled. The authors of the new study are confident that such “missing” stars can be found using the VLT telescope complex and the Keck Observatory if the search parameters are adjusted. Next generation telescopes will enable full-scale observations.