Neutron-Capture Elements in the Double-Enhanced Star HE 1305-0007： a New s- and r-Process Paradigm  

作　　者：崔文元 崔冬暖 杜云霜 张波 

机构地区：[1]Department of Physics, Hebei Normal University, Shijiazhuang 050016 [2]National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 [3]Graduate School of the Chinese Academy of Sciences, Beijing 100049

出　　处：《Chinese Physics Letters》2007年第5期1417-1420,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 10373005, 10673002 and 10778616.

摘　　要：The star HE 1305-0007 is a metal-poor double-enhanced star with metallicity [Fe/H] = -2.0, which is just at the upper limit of the metallicity for the observed double-enhanced stars. Using a parametric model, we find that almost all s-elements were made in a single neutron exposure. This star should be a member of a post-commonenvelope binary. After the s-process material has experienced only one neutron exposure in the nucleosynthesis region and is dredged-up to its envelope, the AGB evolution is terminated by the onset of common-envelope evolution. Based on the high radial-velocity of HE 1305-0007, we speculate that the star could be a runaway star from a binary system, in which the AIC event has occurred and produced the r-process elements.The star HE 1305-0007 is a metal-poor double-enhanced star with metallicity [Fe/H] = -2.0, which is just at the upper limit of the metallicity for the observed double-enhanced stars. Using a parametric model, we find that almost all s-elements were made in a single neutron exposure. This star should be a member of a post-commonenvelope binary. After the s-process material has experienced only one neutron exposure in the nucleosynthesis region and is dredged-up to its envelope, the AGB evolution is terminated by the onset of common-envelope evolution. Based on the high radial-velocity of HE 1305-0007, we speculate that the star could be a runaway star from a binary system, in which the AIC event has occurred and produced the r-process elements.

关 键 词：ASYMPTOTIC GIANT BRANCH METAL-POOR STARS RICH STARS GALACTIC HALO CARBONSTARS DREDGE-UP EVOLUTION NUCLEOSYNTHESIS MODEL ORIGIN 

分 类 号：O57[理学—粒子物理与原子核物理]