For the first time ever, astronomers have observed a rapidly rotating star emitting polarised light, a phenomenon that was predicted over 70 years ago Indian astrophysicist and Nobel laureate Subrahmanyan Chandrasekhar.
A team of researchers from the University of New South Wales (UNSW) in Australia and University College London in the UK have detected that Regulus, one of the biggest stars in the night sky, is emitting light in a unique way and is rotating at such a speed that it is close to "flying apart".
The research has provided extraordinary insight into the star, allowing the scientists to find out the rate of spinning and the orientation in space of the star’s spin axis, according to the study published in the journal Nature Astronomy.
Daniel Cotton, one of the researchers, has claimed that Regulus is spinning at approximately 320 kilometre per second. The speed is equivalent to travelling from Sydney to Canberra in less than a second.
“We found Regulus is rotating so quickly it is close to flying apart, with a spin rate of 96.5 percent of the angular velocity for the break-up,” Daniel, from University of New South Wales (UNSW), Sydney, added.
Chandrasekhar’s prediction in 1946 prompted the development of sensitive instruments called stellar polarimeters to try and detect this effect. In 1968, other researchers built on Chandrasekhar’s work to predict that the distorted, or squashed shape, of a rapidly rotating star would lead to the emission of polarised light, but its detection has eluded astronomers until now.
For this study, the researchers used a highly sensitive piece of equipment designed and built at UNSW Sydney and attached to the Anglo-Australian Telescope at Siding Spring Observatory in westernNew South Wales to detect the polarised light from Regulus.