Australian National University | RSAA | 2015 Jun 23
[img3="The crowded center of the Omega Centauri globular clusterAstronomers have solved a mystery over small, unusually hot blue stars, 10 times hotter than our Sun, that are found in the middle of dense star clusters.
Credit: NASA, ESA, and the Hubble SM4 ERO Team"]http://www.nasa.gov/images/content/3846 ... 24-768.jpg[/img3][hr][/hr]
The international team found the so-called blue hook stars throw off their cool outer layers late in life because they are rotating so rapidly, making them more luminous than usual.
"We've solved an old puzzle. These stars are only half the mass of our Sun yet we could not explain how they became so luminous," said team member Dr Antonino Milone ... "As the star was forming billions of years ago from a disc of gas in the congested centre of the star cluster, another star or stars must have collided with the disc and destroyed it." ...
Usually the large disc of ionised gas around a newly-forming star locks its rotation through magnetic effects. For the progenitors of blue hook stars, however, an early destruction of its disc allows the stars to spin up as the gas comes together to form a star.
Because its high rotation rate partially balances the inward force of gravity, the star consumes its hydrogen fuel more slowly and evolves differently throughout its life. ...
Rapidly rotating second-generation progenitors for the ‘blue hook’ stars of ω Centauri - Marco Tailo et al
- Nature (online 22 Jun 2015) DOI: 10.1038/nature14516
