Tuesday, July 31, 2018

Symphony of Stars: The Science of Stellar Sound Waves

This artist’s concept shows how sound waves travel through a hypothetical star that has an orbiting planet.
Credits: Gabriel Pérez Díaz, Instituto de Astrofísica de Canarias


We can’t hear it with our ears, but the stars in the sky are performing a concert, one that never stops. The biggest stars make the lowest, deepest sounds, like tubas and double basses. Small stars have high-pitched voices, like celestial flutes. These virtuosos don’t just play one "note" at a time, either -- our own Sun has thousands of different sound waves bouncing around inside it at any given moment.

Understanding these stellar harmonies represents a revolution in astronomy. By "listening" for stellar sound waves with telescopes, scientists can figure out what stars are made of, how old they are, how big they are and how they contribute to the evolution of our Milky Way galaxy as a whole. The technique is called asteroseismology. Just as earthquakes (or Earth’s seismic waves) tell us about the inside of Earth, stellar waves -- resulting in vibrations or "star quakes" -- reveal the secret inner workings of stars.  

NASA’s Kepler space telescope, now approaching the end of its mission, has been a key player in that revolution, delivering observations of waves in tens of thousands of stars since its 2009 launch.

NASA’s Transiting Exoplanet Survey Satellite (TESS), which launched in April 2018, may observe sound waves in up to one million red giants -- the massive, evolved stars that represent what our Sun will look like in about 5 billion years. While both Kepler and TESS are most famous for hunting for planets beyond our solar system (exoplanets), they are also powerful, sensitive tools for detecting stellar vibrations. And the more we know about stars, the more we know about planets that orbit them.


Continue reading this story

Written by Elizabeth Landau

Editor: Tony Greicius