Dr. Bill Chaplin

Professor of Astrophysics, School of Physics and Astronomy, University of Birmingham

When you look up at the night sky, did you know that the stars like our Sun are playing their own stellar symphonies, resonating like musical instruments; and we now believe that many of those stars are likely to host planets, like the planets in our solar system. I am a Professor of Astrophysics at the University of Birmingham, and I study the Sun and other Sun-like stars by observing the natural resonances of the stars. We call this field asteroseismology when applied to the stars, and helioseismology when applied to the Sun.

Sound is made naturally in the outermost layers of Sun-like stars. This sound is trapped, with some sound waves penetrating all the way to the centres of the stars. The sound waves are able to reinforce to make the stars resonate at their natural frequencies, like waves inside a wind instrument. The compressions of the trapped sound makes the stars oscillate and we are able to detect this gentle breathing. We can do that by, for example, observing changes in brightness as stars get slightly hotter and brighter as they are compressed and then cooler and darker as they relax.

We use this “music of the spheres” to not only estimate the properties of the stars, such as their size, mass and age, but we may also peel away their surface layers to probe the structure and dynamics of their normally hidden interiors. I am leading international teams of scientists using data from the NASA Kepler Mission to characterise stars with newly discovered planets. Without the information on the stars, we cannot fully describe the planets we have found: to say for example, whether we might have found an Earth-sized planet in the habitable zone of its star.  Our work is opening up new stellar systems elsewhere in the Galaxy to detailed, forensic study, and also helping us to better understand the interactions we have with our own star, the Sun.