Misunderstanding the Sun: microscopic uncertainties in the standard solar model

Speaker:Prof. Doron Gazit
Affiliation:Hebrew University in Jerusalem
Organizer:Hagai Perets
Time:14:30 - 15:30
Location:Lidow Rosen Auditorium (323)
Over the past decade, an outstanding open problem in solar physics has emerged, as solar photospheric abundances of metallic elements have been significantly revised downward. Standard solar models do not reproduce helioseismic measurements, such as the convection zone radius, the surface helium abundance and the sound speed profile, when using these revised abundances. This gave rise to the solar composition problem, motivating a rapid growth of research efforts in the field.

With this problem of in mind, I study theoretically two main microscopic phenomena occurring in the Solar interior, namely, nuclear solar fusion and electronic heat conduction in the solar plasma, and discuss theoretical uncertainties. Both microscopic phenomena have a significant effect on solar evolution, but cannot be approached in terrestrial experiments today. Moreover, I argue that the solar opacity problem is hindered due to the large uncertainties. In the case of heat conductivity at the extremely hot and dense matter of the Sun, a method is outlined to measure opacities via laboratory radiation flow experiments, which allow probing solar thermodynamic conditions deeper than ever before into the Sun.
The effect of the new assessment of solar proton-proton fusion rate on neutrino fluxes will be briefly discussed.