题目：Internal structure and interior composition of Jupiter from JUNO 

　　时间：2019年7月26日（星期五）上午10:00—11:00 

　　地点：三楼中会议室 

　　报告人：Dr. Dongdong Ni（倪冬冬）, State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology 

　　摘要： 

The Juno spacecraft has significantly improved the accuracy of low-order even gravitational harmonics. It has been demonstrated that a dilute core, with the heavy elements dissolved in the metallic hydrogen envelope and expanded outward through a portion of Jupiter's interior, is helpful to interpret Juno's gravity measurements. We present four-layer structure models for Jupiter where a dilute core region is added above a central compact core of rocks. The effect of the dilute core on the structure and composition of Jupiter is investigated in details. Combined with current knowledge of Jupiter's composition and thermal state, we aim to achieve some information on the dilute core. Also, we investigate the effect of equations of state for hydrogen and helium on the predictions of the core mass and heavy element abundance within the four-layer structure framework. It is found that the absolute values of J6 and J8 tend to decrease as helium becomes more depleted in the dilute core region, showing better agreement with Juno's gravity observations. The interior structure calculations seem to prefer an inward decrease of the helium mass fraction from the metallic envelope to the dilute core region. We also show that the core mass and heavy element abundance in Jupiter are dependent upon the rock-to-ice ratio in the dilute core region, the temperature jump from the molecular to metallic envelope, and the equations of state for hydrogen and helium. The resulting heavy element mass in the core is generally larger than the three-layer structure models owing to the heavy elements dissolved in the dilute core region and the global heavy element abundance is in good agreement with the available dilute core predictions. 

　　Dongdong Ni（倪冬冬）： 

After obtaining his PhD degree in theoretical physics from the Dept. of Physics, Nanjing University in 2012, he spent another two years in Nanjing University as Postdoc working on nuclear physics and particle physics, before joining Macau University of Science and technology in 2015. At present, he is the assistant director of the State Key Laboratory of Lunar and Planetary Sciences, also an world class expert on first principle calculations of equation of state for planetary matter under high pressure and temperature condition.