Helioseismology: A Window into the Sun

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Session 39 -- Hale Prize Lecture
Invited presentation, Tuesday, 10, 1995, 8:30am

[39.01] Helioseismology: A Window into the Sun

Douglas Gough (University of Cambridge)

The sun is vibrating in many modes simultaneously. By listening to the tones one can try to recognise its structure, just as one can recognise from its sound a particular musical instrument in a symphony orchestra. The importance to astrophysics is that it is possible to use the information to test the theory of the structure and evolution of stars, and to calibrate theoretical models of the sun.

Once we know the internal state of the sun, we have at our disposal a valuable laboratory in which we can carry out physical measurements under conditions that cannot be achieved on Earth. Already, such measurements have caused a revision in calculations of atomic radiative transitions in dense plasmas, which has resolved several long-standing problems in stellar astrophysics. The measurements have also put tight constraints on the structure of the energy generating core, and have thereby eliminated many of the suggestions that have been offered to resolve the solar neutrino problem. Moreover, they have provided us for the first time direct and somewhat surprising information about the internal rotation, which has caused us to rethink our ideas about the evolution of the angular momentum and about the generation of the Sun's magnetic field.

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