Helio- and Asteroseismology



The purpose of helio- and asteroseismology is very similar to trying to determine the shape and construction of musical instruments from the sounds that they make. The way in which something can vibrate, whether it is a star or an elastic band, can say a lot about what it is. We all know how to recognize the difference between a drum and an organ or a bell. In helioseismology we try to be much more precise and quantitative in what we determine about the Sun : which is something like trying to hear the difference between a Stradivarius and an ordinary violin.

The term helioseismology comes from a combination of three words :

  • helios : from the classical Greek which means Sun or light.
  • seismos : also from Greek meaning tremor.
  • logos : meaning reasoning or discourse.
So literally translated helioseismology is the study of solar tremors, just as geoseismology is the study of earthquakes, and in particular the use of the information on how eartquakes propagate to measure the internal structure of the earth. By looking at tremors on the solar surface it is possible to measure what the Sun is like, deep in its interior ! How this is done is described on the page on solar oscillations. You can also read about how we observe the Sun and other stars.

Asteroseismology is the study of oscillations on distant stars for which we use much the same techniques that are used in helioseismology. It is just made more difficult by the fact that stars are a lot further away than the Sun. You can read more about asteroseismology done at Aarhus university here.

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