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

作　　者：Chun-Guang Zhang Li-Cai Deng Da-Run Xiong Jrgen Christensen-Dalsgaard 

机构地区：[1]Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Purple Mountain Observatory, Chinese Academy of Sciences [4]Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University

出　　处：《Research in Astronomy and Astrophysics》2013年第9期1127-1140,共14页天文和天体物理学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 10773029 and 10973015);the National Basic Research Program of China (973 program; Grant No. 2007CB815406);received funding from the exchange programme between Chinese Academy of Sciences and the Danish Rectors’ Conference (UniversitiesDenmark);Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant DNRF106);supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (Grant No. 267864)

摘　　要：Local mixing-length theory is incapable of describing nonlocal phenom- ena in stellar convection, such as overshooting. Therefore standard solar models con- structed with local mixing-length theory significantly deviate from the Sun at the boundaries of the convection zone, where convection becomes less efficient and nonlo- cal effects are important. The differences between observed and computed frequencies mainly come from the region near the surface, while the localized difference in sound speed is just below the convective envelope. We compute a solar envelope model using Xiong＇s nonlocal convection theory, and carry out helioseismic analysis. The nonlocal model has a smooth transition at the base of the convection zone, as revealed by helio- seismology. It reproduces solar frequencies more accurately, and reduces the localized difference in sound speed between the Sun and standard solar models.Local mixing-length theory is incapable of describing nonlocal phenom- ena in stellar convection, such as overshooting. Therefore standard solar models con- structed with local mixing-length theory significantly deviate from the Sun at the boundaries of the convection zone, where convection becomes less efficient and nonlo- cal effects are important. The differences between observed and computed frequencies mainly come from the region near the surface, while the localized difference in sound speed is just below the convective envelope. We compute a solar envelope model using Xiong＇s nonlocal convection theory, and carry out helioseismic analysis. The nonlocal model has a smooth transition at the base of the convection zone, as revealed by helio- seismology. It reproduces solar frequencies more accurately, and reduces the localized difference in sound speed between the Sun and standard solar models.

关 键 词：convection -- Sun： interior -- Sun： helioseismology 

分 类 号：P182[天文地球—天文学] P18