Seismic study of solar convection and overshooting: results of nonlocal convection

摘要

Local mixing-length theory is incapable of describing nonlocal phenomena instellar convection, such as overshooting. Therefore standard solar modelsconstructed with the local mixing-length theory deviate significantly from theSun at the boundaries of the convection zone, where convection becomes lessefficient and nonlocal effects are important. The differences between observedand computed frequencies come mainly from the near-surface region, while thelocalized sound-speed difference is just below the convective envelope. In thispaper we compute a solar envelope model using Xiong's nonlocal convectiontheory, and carry out helioseismic analysis. The nonlocal model has a smoothtransition at the base of the convection zone, as revealed by helioseismology.It reproduces solar frequencies more accurately, and reduces the localizedsound-speed difference between the Sun and standard solar models.