News release: University wins grant for new stellar research

Abstract

As galaxies collide thousands of light years away the world's leading authority on roAp stars is preparing to investigate the pulsation modes and magnetic fields in some of the universes most peculiar stars.

Professor Donald Kurtz, from the University of Central Lancashire's Centre of Astrophysics, was recently awarded a standard research grant from PP ARC (Particle Physics and Astronomy Research Council) for his research proposal 'Stellar Spectroscopy for astroseismology'. The grant will pay for a three year postdoctoral research assistant to work with Professor Kurtz in collaboration with Dr. Gautier Mathys at the European Solar Observatory in Chile. The UK has recently paid an admission fee in the region of £65 million to join the observatory giving British astronomers regular access to the telescope from 2002. Sitting on top of Mount Paranal in the Atacama Desert, the observatory contains a £200,000 million machine, Chile's largest telescope.

Professor Kurtz specializes in variable stars, which vibrate and change their shape, size and brightness. Variable stars contain sound waves but as the sound can't escape the sound waves moving in the star cause it to pulsate. The rate of vibration varies, simple ones contract like a blown up ball. Others have extremely complex vibrations with various things going in and out, various parts of the star get hotter and cooler. The frequency, or period, and vibrations are down to the sound speed which depends on the temperature, the density and the frequal composition. Breaking the process down Professor Kurtz relates the phenomenon to that of an orchestra.

"If someone was sitting with their back to an orchestra with their eyes closed whilst the orchestra is tuning up. Every instrument is playing the same note but if they listen they'll be able to pick out the oboe, the violin, the flute. They can pick out the different instruments even though they're playing exactly the same note. What makes the sound different with different instruments even though they're playing the same frequency? The shape of the instruments; the resonator shapes the note.

"Musical instruments produce harmonics that shapes the waves, so in many cases it pushes your eardrum in quickly and then let it out slowly. A square wave is where it may push it in quickly and hold it there for a while then let it out quickly. Push it in quickly and let it out slowly is called a triangular wave. The shape of the instrument shapes a sound wave and in your mind you can actually picture the instrument. The character and the frequencies of any oscillating object will tell you what the objects like.