Scientific Insights from SOHO, 2003 -2005: Helioseismology and Solar Interior

Recently determined heavy element abundances 1-3 have led to significant changes in our understanding of the internal structure and constitution of the Sun. It turns out that the standard solar models calculated with the new abundances are significantly different from the helioseismic results which were in a good agreement with the previous solar models. Figure 1 shows the relative difference between the MDI measurements of the soundspeed profile inside the Sun and various solar models. The solid curve shows the difference for a standard solar model with the previously known solar composition. The dotted curve shows this difference for the standard model computed with the new composition which has lower abundances of oxygen and iron as determined spectroscopically by Asplund).