Nuclear reactions in the crusts of accreting neutron stars

  

  报告题目:Nuclear reactions in the crusts of accreting neutron stars 

  报告人Dr. Kit Yu Lau, Rita (Hong Kong Community College)  

  时间2019130日(星期三)10:00 

  地点:近代物理所工艺楼六楼会议室 

  摘要:The compositions of the crusts of accreting neutron stars in binary systems is determined by the ashes of hydrogen and helium burning at the neutron star surface, and the nuclear processes deeper in the crust that convert the proton rich ashes into neutron rich nuclei. These nuclear processes operate continuously driven by the mass accretion, cool and heat the crust creating. Because of the limited thermal conductivity this results in a characteristic temperature profile, which can be observed in transient systems when the accretion shuts off for extended periods of time. We carried out detailed nuclear reaction network calculations that identify the nuclear processes in the crust of accreting neutron stars. These reactions include electron captures with neutron emission, beta decays with neutron emission, beta decays with neutron emission, neutron capture and dissociation, and pycnonuclear fusion reactions. The result is significantly different from previous work. Furthermore, we confirmed that the inner crusts in general are very pure and independent of the initial abundance. We further conclude that cooling due to Urca processes in the outer crusts heavily depend on the initial abundance. 

   

  报告人:Kit Yu Lau Rita2005年毕业于香港中文大学,获学士学位;2012年毕业于密歇根州立大学,获物理学博士学位。现任职于Hong Kong Community College主要从事x射线暴、r过程、致密星体核过程等方面的研究。曾获得“INFN 2013/2014年度奖学金”。