談對恆星在絲狀暗星雲中形成作數值模擬


Seminar: Numerical Simulation of Star Formation in Filamentary Dark Clouds 
 
Observations show that the star formation process starts form the giant molecular cloud (GMC) complex of several tens of parsecs all the way down to the formation of protostars at the size scale of solar radius (9 orders of magnitude in spatial scale). In between, we observe long filamentry dark clouds, large molecular cloud clumps, dense cloud cores which house protostellar formation, and protostellar accretion disks. Numerical simulation becomes a powerful tool to understand and connect these observational snapshots of the whole star formation process. Multiply coupled highly non-linear physics are involved in the process, including magnetic field, supersonic turbulence, gravity, radiation and protostellar outflow feedback. It is a challenge to simulate the entire process in a single numerical simulation. To achieve such a long-term challenge, we need efficient adaptive codes, such as adaptive mesh refinement (AMR) code, that can manage memory usage efficiently and are highly scalable on large-scale high performance supercomputers. In this talk, I present some highlights of our simulation results, using our radiative-magnetohydrodynamics AMR code"ORION2", on (1) the intertwined filamentary structure of dark clouds, (2) the magnetic properties of the dense cloud clumps, and (3) the protostellar cluster formation in a highly supersonic turbulence region of 4.55 parsecs in size to the maximum resolution of 28 astronomical units. Our simulation results match well with the latest observations and provide important insight into the process of star formation at different size scales. 
 
時間:2016.02.01(一) 16:00
地點:香港大學 莊月明物理樓 522室
講者:Dr. Pak Shing LI 李北誠 博士 (Astronomy Department University of California at Berkeley, USA) 
語言:英語

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此活動由香港大學物理學系主辦。

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