Caption:Mixed modes in a red giant.
Further information:This computer generated animation illustrates waves, or "stellar oscillations" as astronomers call them, in red giant stars. The amplitude has been exaggerated to make the waves better visible, and the oscillations are sped up. In reality, one oscillation takes several hours. In the first scene a crosscut from the surface to the core of the red giant is given. Colors were chosen so that the eye can easily follow the waves. In the outer region of the star the gas particles are moving back and forth, compressing and decompressing the gas, quite similar as for sound waves on Earth. Most waves inside red giant stars fade out towards the core, but the waves detected now intensify again in the core of the giant star. The second scene zooms in on the core to illustrate this. Note that the waves inside the core behave quite differently from the ones in the outer region. This is the artist impression for Beck et al. (2011) Science 332, 205. It was calculated by Pieter Degroote (IvS, KU Leuven, Belgium). and published as the NASA Astronomy Picture of the Day by Degroote, Beck, De Ridder, Aerts & Carrier (all IvS, KU Leuven, Belgium) on April 8, 2011: http://apod.nasa.gov/apod/ap110408.html
Link this video: http://www.science-media.org/67