A group of researchers from Northwestern University has been able to explain the appearance of unusual stars that orbit around the central supermassive black hole of the Milky Way.
Their scientific paper, published in The Astrophysical Journal Letters, helped understand that these stars, often referred to as “zombies,” appear younger than they actually are because they absorb material from other stars.
Scientists noted that dense stellar clusters in the vicinity of the Milky Way’s black hole, Sgr A*, contain hundreds of thousands of stars colliding with each other at tremendous speeds. Approximately 10% of such stars deviate from the usual evolution due to collisions. Interestingly, collisions occur most often between tightly bound stars that orbit the black hole faster than others.
Researchers resorted to modeling to track the fate of these stars. They took into account several factors, including the cluster’s density, star mass, orbital velocity, and gravity.
As a result of collisions, some stars gather more hydrogen, making them appear younger. However, in reality, their lifespan decreases as they quickly deplete their hydrogen reserves, the authors concluded.
Photo: freepik.com