(ORDO NEWS) — Some people try to look younger than they really are – and stars too! This is reported by an international team of astronomers in a new study.
In their work, these scientists suggested that stars in star clusters can gain mass in two different ways – as a result of “normal” accretion from the disk, leading to the star’s rapid rotation and acquiring the properties of a “red” main sequence star, or as a result of the union of binary stars leading to slowly rotating stars that are closer to blue and therefore appear younger.
Everyone who is interested in astronomy knows the famous color-luminosity diagram, also called the Hertzsprung-Russell diagram. Most of the stars in this diagram belong to the so-called “main sequence”, including our Sun.
However, recent observations, in particular with the Hubble Space Telescope (Hubble), have revealed inexplicable features in some clusters of stars – for example, in the open cluster NGC 1755, belonging to the Large Magellanic Cloud and characterized by an average age of stars in 60 million years, a main sequence bifurcation was discovered.
Despite the fact that all the stars in the cluster formed from the same cloud and have approximately the same age, some of these stars are closer to blue, forming a second, “blue” main sequence.
To explain this fact, a team led by Chen Wang computer-simulated the evolution of the stars in the cluster and showed that blue stars can be explained if they are assumed to rotate more slowly than red main-sequence stars.
Secondly, modern models of mergers between stars have shown that the resulting stars acquire a powerful magnetic field and rotate very slowly.
Chen combined these two ideas and suggested that blue stars are actually very slowly rotating luminaries, formed as a result of collisions between the original stars of low masses. This new mechanism for the formation of massive stars in young star clusters could be responsible for nearly a third of the cluster’s stars, Chen said.
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