Advancing the accuracy of asteroseismic age determinations of old-disk stars using an oscillating red giant in an eclipsing binary

Inferring stellar mass through sound

A clarinet, a saxophone, and a red giant star, each connected to a distinct spectrum of vibrations that forms its acoustic fingerprint.

Credits: stellar oscillations animation generated with gpulse3d (Stephane Charpinet, IRAP Toulouse)

The star's oscillations, originally occurring at around 20 microhertz (roughly one oscillation every 14 hours), have been multiplied by about 6.5 million to bring them into the audible range: the result is a 130 Hz tone, corresponding to C3, the same note played by the clarinet and saxophone in the animation.
Although the clarinet and saxophone both play the same fundamental note (C3), their spectra are different: this is their unique timbre, shaped by their form and internal structure. The same is true for stars: they also vibrate, and their internal oscillations produce tiny variations in brightness that we can measure with telescopes like Kepler. By analyzing the distribution of these frequencies we can infer the mass, radius, and age of a star.

or watch the animation on youtube:



Illustration of the eclipsing binary system KIC 10001167

Left: the variation in light observed over time shows the periodic eclipses of the two stars. Right: the top-down view of the orbits of the two components (a red giant and a dwarf star), along with the variations in their velocities along the line of sight. By combining these data -light curves and radial velocities- astronomers can determine the masses and radii of stars with great precision.