Stellar Seismology

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My research is primarily directed toward understanding how stars work by analyzing the harmonic structure of sound waves that bounce around their interiors. The sound waves are not heard but seen. As a sound wave travels through the interior of a star it causes the material of the star to oscillate up and down into warmer and cooler regions of the star. The changes in temperature of the material can be seen on the surface of a star as minute variations in the star's brightness. From the brightness fluctuations, we can deduce the frequency and amplitude of the sound waves, which, in turn, can be used to build a picture of what is going on inside the star. Our methods are in many ways similar to the techniques used by seismologists to map out the composition of the interior of the earth using the vibrations produced by earthquakes.In order to clearly see the fluctuations we need to observe the same star continuously for at least a couple of weeks, without interruption from weather and daylight. In addition, we need to avoid the twinkling effects of the earth's atmosphere. Therefore, we must observe from a "space telescope" specifically designed and dedicated to observing the tiny variations in light. Canadian scientists were the first to build and launch such a satellite. The satellite, called MOST (Microvariability and Oscillations on STars), has been in operation now for over three years. My research colleagues and I have been analyzing the data obtained from the satellite to build a detailed picture of the interiors of sun-like stars.I will soon direct my attention to pre-main-sequence and giant stars. Pre-main-sequence stars are young stars, recently formed, still collapsing, and not yet burning nuclear fuel. Giant stars are swollen stars, near the end of their life. I along with other asteroseismologists (as we have come to call ourselves) hope to build a well constrained model of the birth, life, and death of stars like our sun.