Measuring stars to reveal greater understanding of the Sun

Posted on Thursday 28th October 2010

Researchers from the University have detected a star in our galaxy that is older and bigger than our Sun and has certain characteristics that give a clear indication of its age and internal properties. It is hoped this can give us insight into the behaviour of the sun and to develop a greater understanding of the evolution of stars and our galaxy.

The star in question, called Gemma, is bigger and a lot older than the Sun. Birmingham physicists have been able to measure the size, mass, radius and age of this star due to data that is collected from the NASA Kepler mission.

Stars are characterized using the natural pulse of their light waves. These variations in brightness can be translated into ringing vibrations, or oscillations, within the stars using a technique called asteroseismology. The oscillations reveal information about the internal structure of the stars, in much the same way that seismologists use earthquakes to probe the Earth’s interior. This information allows the properties of stars, such as their mass, size and age, to be measured to exquisite precision.

Dr Bill Chaplin from the University’s School of Physics and Astronomy, said ‘Stars ring or vibrate like musical instruments. If you measure the pitch of an instrument, you can tell how big it is - the bigger the instrument, the lower the pitch and deeper the sound. This is how we can tell how big stars are.  We can also estimate their ages.  We find that as stars get older, they go through a state where they become less ‘tuneful’, and Gemma is in this state.We hope that by studying stars in this way it will also give us a greater understanding of the Sun, what drives the variability of the Sun, and why it has quiet and active periods.’

Listen to the star sound made by Gemma

For further information about this story, you can read the Singing Stars press release.