"Nearby young stars have revealed 'danger zones' where planet formation may be at risk."

O-type stars are massive, hot celestial bodies that exhibit white-blue or blue colors, forming what are known as O-type associations — groups of gravitationally unbound or loosely bound stars. It is believed that they share a common origin, emerging from a giant molecular cloud, and their age does not exceed a few million years.

Cygnus O2 is one of the most massive and brightest O-type associations known to science. It is there that the authors of a new study, published in the journal The Astrophysical Journal, discovered so-called hazardous zones — areas near massive young stars, whose radiation interferes with planet formation and may even render it impossible.

The conclusion was reached by a team of astronomers led by Mario Guarcello (Mario Guarcello) from the National Institute of Astrophysics (Italy) after analyzing data from long-term observations obtained through the Chandra X-ray Observatory and the decommissioned Spitzer Infrared Telescope.

Given that the observed star association contains both stars with protoplanetary disks and those without, the researchers examined their spatial distribution and found that the radiation from massive stars (along with the intense ultraviolet radiation from smaller stars) significantly accelerated the destruction of protoplanetary disks. Subsequently, by combining the observational data, the astronomers created a detailed mosaic of the region.

This approach allowed them to locate young stars and areas of intense radiation within the cluster, leading to the conclusion that the high-energy radiation from massive young stars causes rapid evaporation of protoplanetary disks around nearby stars, thereby hindering and even preventing planet formation.

The scientists also discovered that in areas with fewer massive stars (and thus lower levels of high-energy radiation), approximately 40 percent of young stars possessed protoplanetary disks. However, in regions with more intense radiation and higher star density, this proportion dropped to 18 percent. In the most densely populated areas, the number of stars with protoplanetary disks fell to one percent.

It is noteworthy that star formation in the Milky Way occurs in various environments, and a significant portion of stars forms in clusters where massive O and B-type stars are present. This is because these stars have a substantial impact on both the evolution of protoplanetary disks around neighboring young stars and on the processes of planet formation. While conditions for planetary system formation are favorable in the calmer regions of our galaxy, areas near massive stars have proven to be "hazardous zones," where the likelihood of planet formation is significantly reduced.

The results of this new study help to identify the mechanisms influencing the evolution of protoplanetary disks and are crucial for understanding the broader picture of planet and star formation. Further observations, according to the authors of the scientific work, will help clarify which processes dominate in various environments and how they interact with one another.