Helioseismology from the South Pole: 1987 campaign

Helioseismology is the study of the Sun's interior by means of observations of its global oscillations. The Sun constantly oscillates, at periods of about 5 minutes, in millions of different modes which probe different depth and latitude ranges. Helioseismological observations have been made from the Amundsen-Scott South Pole Station nearly every year since 1980. This site offers the unique advantage of uninterrupted sunlight during the austral summer (except for clouds, of course) and otherwise generally good atmospheric conditions for astronomical observations. Thus, it is possible to measure oscillations without long nighttime gaps which confuse measurements made at low-latitude observatories. Measurements from the South Pole and elsewhere have shown that the solar interior is roughly similar to the predictions of the theory of stellar structure and evolution. This theory is one of the key foundations of our present picture of the universe. It is, therefore, disturbing that there are small, but highly significant, discrepancies between theory and observations and that these discrepancies have not been resolved by reasonable adjustments of theoretical parameters and physics. Currently, the source of these discrepancies is not at all clear. Helioseismology, however, not only revealed the problem but offers excellent prospects for solving it