Taking a musical approach helps scientists determine how much a star should shine
ASTRONOMY
Scientists have developed a new method to predict the brightness of a star’s inherent twinkle. What’s more, they’ve also managed to simulate how that twinkle might sound. And it seems that massive stars sing a strangely eerie song (hear an example for yourself on the BBC Science Focus website at bit.ly/InherentTwinkle).
Unlike the visible twinkle we see from Earth, which is caused by a star’s light being distorted as it passes through this planet’s atmosphere, a star’s inherent twinkle is caused by rippling waves of gas on its surface.
The gas waves originate in the nuclear reactions that take place in a star’s core and move out towards the surface. As they move, the waves create turbulence and chaos in the gases around them, increasing or decreasing the star’s shine to produce its inherent twinkle. This inherent twinkle is invisible, however – to the naked eye as well as the current generation of powerful ground-based telescopes.
But a team, led by scientists from Northwestern University in Illinois, America, has developed a method to produce 3D simulations of the gas waves moving from a star’s core to its surface. These simulations have, for the first time ever, enabled the scientists to determine a given star’s inherent twinkle.
The new method, which was detailed in a study published in the journal Nature Astronomy, may help us learn more about what’s happening inside massive stars (those more than 1.2 times larger than the Sun). Furthermore, it has the potential to shed light on how stars and galaxies form and evolve, as well as help explain how the elements we depend on – such as oxygen – are created.
“Motions in the cores of stars launch waves like those on the ocean,” said Dr Evan Anders, who led the study. “When the waves arrive at the star’s surface, they make it twinkle in a way that astronomers may [one day] be able to observe.”
But how did they come up with the sounds of those stars’ twinkles?
After developing the simulations into computer models and using the models to calculate how much twinkling is caused by different frequencies and intensities of waves, Anders and his team then converted these calculations into an audio track to illustrate the movement of the waves.
The resulting track is a human ‘translation’ of the song, however, because the waves are outside the range of human hearing. As such, the researchers had to increase
