NBIA Colloquium – Niels Bohr Institute - University of Copenhagen

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NBIA Colloquium

Speaker: J. Christensen-Dalsgaard (Univ. of Aarhus)

Title: Singing Stars

Abstract:  Eddington noted in 1926 that `[a]t first sight it would seem that the deep
interior of the sun and stars is less accessible to seismic investigation
than any other region of the universe'. Although theoretical modelling,
spearheaded by Eddington, provided a means to probe these regions it is
only fairly recently that direct observational information about them has
become available. Crucial in this regard has been the detailed observations
of solar and stellar oscillations, reflecting global modes involving large
parts of the stars, which are sensitive to the detailed structure and  
dynamics of the stellar interiors. Studies of solar oscillations have provided
detailed inferences of the structure and rotation of the solar interior.
This gave early evidence that the observed deficit of neutrinos from the Sun
did not reflect errors in solar modelling; however, recent updates in the
determination of the solar surface composition have led to other difficulties
with solar models. Similar studies of other stars have been constrained by
observational limitations which are now being overcome through observations
from space as well as through the establishment of a world-wide network
of asteroseismic observatories.