Discovery of a strongly r-process enhanced extremely metal-poor star LAMOST J110901.22+075441.8  

作　　者：Hai-Ning Li Wako Aoki Satoshi Honda Gang Zhao Norbert Christlieb Takuma Suda 

机构地区：[1]Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences [2]National Astronomical Observatory of Japan,2-21-1 Osawa,Mitaka,Tokyo,181-8588,Japan [3]Department of Astronomical Science,School of Physical Sciences,The Graduate University of Advanced Studies (SOKENDAI),2-21-1 Osawa,Mitaka,Tokyo 181-8588,Japan [4]University of Hyogo,Center for Astronomy,Nishigaichi,Sayo-cho,Sayo,Hyogo,679-5313,Japan [5]Zentrum für Astronomie der Universitt Heidelberg,Landessternwarte,Knigstuhl 12,D-69117 Heidelberg,Germany [6]Research Center for the Early Universe,The University of Tokyo,Hongo 7-3-1,Bunkyo-ku,Tokyo 113-0033,Japan

出　　处：《Research in Astronomy and Astrophysics》2015年第8期1264-1274,共11页天文和天体物理学研究（英文版）

基　　金：the paper.H.N.L.and G.Z.acknowledge supports by the National Natural Science Foundation of China (Grant Nos.11103030, 11233004 and 11390371);W.A.and T.S.are supported by the JSPS Grant-in-Aid for Scientific Research (S: 23224004);S.H.is supported by the JSPS Grant-in-Aid for Scientific Research (c:26400231);N.C.acknowledges support from Sonderforschungsbereich 881 "The Milky Way System" (subproject A4) of the German Research Foundation (DFG)

摘　　要：We report the discovery of an extremely metal-poor（EMP） giant,LAMOST J110901.22＋075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ～ ＋1.16. The star is one of the newly discovered EMP stars identified from the LAMOST low-resolution spectroscopic survey and a highresolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22＋075441.8. The abundance pattern of LAMOST J110901.22＋075441.8 in the range of C through Zn is in line with the ＂normal＂ population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22＋075441.8 is in agreement with other well studied cool r-II metal-poor giants such as CS 22892-052 and CS 31082-001. The abundances of elements in the range from Ba through Dy match the scaled solar r-process pattern well.LAMOST J110901.22＋075441.8 provides the first detailed measurements of neutroncapture elements among r-II stars at such low metallicity with [Fe/H]-3.4, and exhibits similar behavior as other r-II stars in the abundance ratio of Zr/Eu as well as Sr/Eu and Ba/Eu.We report the discovery of an extremely metal-poor（EMP） giant,LAMOST J110901.22＋075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ～ ＋1.16. The star is one of the newly discovered EMP stars identified from the LAMOST low-resolution spectroscopic survey and a highresolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22＋075441.8. The abundance pattern of LAMOST J110901.22＋075441.8 in the range of C through Zn is in line with the ＂normal＂ population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22＋075441.8 is in agreement with other well studied cool r-II metal-poor giants such as CS 22892-052 and CS 31082-001. The abundances of elements in the range from Ba through Dy match the scaled solar r-process pattern well.LAMOST J110901.22＋075441.8 provides the first detailed measurements of neutroncapture elements among r-II stars at such low metallicity with [Fe/H]-3.4, and exhibits similar behavior as other r-II stars in the abundance ratio of Zr/Eu as well as Sr/Eu and Ba/Eu.

关 键 词：star： abundances—stars： PopulationⅡ— nucleosynthesis 

分 类 号：P148[天文地球—天体物理] TH751[天文地球—天文学]