ACTON, Australia, June 23 (UPI) -- Blue hook stars have confused scientists for many years. Found in the center of many star clusters, blue hook stars are just half the mass of our sun, yet ten times hotter and much more luminous.
Finally, researchers say they know why. In a new study, a team of scientists say the blue star's unique disposition is a result of its unusual birth and evolution.
Its characteristics are the result of an early stellar collision, researchers say.
"As the star was forming billions of years ago from a disc of gas in the congested center of the star cluster, another star or stars must have collided with the disc and destroyed it," researcher Antonino Milone, an astronomer at the Australian National University, explained in a press release.
"These blue stars must form in a second generation of star formation," Milone said. "Our new explanation is quite simple, and it hangs together really nicely."
Not only do stars in star clusters not all form at once, researchers realized, they also don't all form the same way.
Stellar discs limit the rotation of the young star, but without it, the blue star's spin rate accelerates. The fast rotation counteracts the inward pull of gravity, causing the star to consume gas at a slower rate. The diminished metabolism affects the star's evolution, allowing it to accumulate a denser heavier core over time -- but without increasing its mass.
Blue hook stars take on their unique characteristics after 10 billion years, once they have burned through all the available hydrogen and begin consuming helium. Helium burns extra hot, giving the star its bright, blue heat.
The new research was published in the journal Nature this week.