Asteroseismology

First published: 2010

Brief summary

NASA overview of stellar oscillations used to infer internal structure.

Article

Asteroseismology studies oscillations within stars by measuring small, repeated changes in brightness or motion at the stellar surface. These variations arise from waves that travel through the interior and are modified by the density, temperature, composition and rotation of the layers they cross.

Stars can support many oscillation modes at the same time. Pressure modes are restored mainly by pressure and are most sensitive to outer regions, while gravity modes are restored by buoyancy and provide information about deeper stellar layers.

Space telescopes such as Kepler recorded long, nearly continuous stellar light curves. Frequency analysis separates the overlapping oscillations and allows astronomers to measure characteristic spacings, mode lifetimes, amplitudes and rotational splitting.

Comparisons between observed frequencies and stellar models constrain mass, radius, age, internal rotation and evolutionary state. The method can characterise stars that host exoplanets and test models of stellar structure more precisely than surface observations alone.

Source details and credits

• Source / publisher: NASA Kepler
• Source type: Educational article
• URL type: WWW
• Credits: NASA Kepler
• URL: https://science.nasa.gov/mission/kepler/science/asteroseismology/