原太阳吸积盘结构

THE STRUCTURE OF PROTOSOLAR ACCRETION DISK

计算了粘滞演化阶段原太阳吸积盘结构 .采用稳态标准吸积盘模型来描述盘中湍动粘滞 ;忽略其径向能量传输 ,将垂直结构作为一维问题处理 .假设盘作Keplerian较差旋转 ,处于流体力学平衡和局域热平衡 ,盘由粘滞耗散加热 ,能量通过对流和辐射向外传输 .结果表明 ,对温度敏感的不透明度是决定盘结构的重要因素 ;原太阳吸积盘为冷的薄盘 ,盘中热对流不稳定性由外而内 ,由上而下地终结 ;行星的形成应首先开始于对流终结的区域 .

The structure of protosolar accretion disk during viscous diffusion stage is calculated. The standard α model is used to describe the viscosity in the optically thick protosolar accretion disc. The energy transport associated with radial motions is neglected and the vertical structure is constructed by assuming a Keplerian rotation and local hydrostatic and thermal equilibrium. The disk is heated by viscous dissipation and energy is transported by convection or radiation. It is found that the dependence of opacity on temperature is important to the disk structure. For the cold protosolar accretion disc, convective instability will gradually end from the outer region to the center and from the surface to central plane. So the formation of planets should first take place in the region where convection ends.