学 术 报 告

报告题目

Mass transfer in AGB binaries  Picture 

报告时间  2020年1月3日周五下午3:30 
报告地点  东七楼427 
报告人  陈卓 博士 
报告人单位  University of Alberta 
邀请人  吴庆文 教授 
报告内容 

摘要

The origin of chemically peculiar stars and non-zero eccentricity in evolved close binaries have been long-standing problems in binary stellar evolution. Answers to these questions may trace back to an intense mass transfer during an AGB binary phase. In this talk, I will discuss two mass transfer modes in the AGB binaries and the transition between them. One mass transfer mode is Bondi-Hoyle-Lyttleton (BHL) accretion and the other is Wind-Roche-lobe overflow (WRLOF). We use AstroBEAR to solve radiation-hydrodynamic equations in 3D and calculate mass transfer rates in asymptotic-giant-branch (AGB) binaries with different binary separations. Accretion disks may form around the secondaries. Depending on the binary separation, a circumbinary disk or a spiral structure may appear in the simulation. The resulting mass transfer efficiency in our models is up to a factor of 8 times higher than what the standard BHL accretion scenario predicts, and the outflow gains up to 91% of its initial angular momentum when it reaches 1.3 binary separations. Consequently, some AGB binaries may undergo orbit shrinkage, and some will expand. The high mass transfer efficiency is closely related to the presence of the circumbinary disks. 
报告人 

简介

Sept 2007-Jul 2012: B.Sc. in Engineering Mechanics, Tongji University, China. 

Aug 2012-Mar 2014: M.Sc. in Mechanical Engineering, University of Rochester, USA.

Jan 2014-Mar 2018, Ph.D. in Astronomy, University of Rochester, USA.

Sept 2018- Aug 2020, CITA National Postdoctoral Fellow at the University of Alberta

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