Evaluating Helium Variations By Modeling Red Giant Branch Bump of Large Magellanic Cluster NGC 1978  

作　　者：Xin Ji Cheng-Yuan Li Li-Cai Deng 

机构地区：[1]Key Laboratory for Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [2]School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China [3]School of Physics and Astronomy,Sun Yat-sen University,Zhuhai 519082,China [4]Department of Astronomy,School of Physics and Astronomy,China-West Normal University,Nanchong 637002,China

出　　处：《Research in Astronomy and Astrophysics》2022年第3期72-79,共8页天文和天体物理学研究（英文版）

基　　金：support through Grant Nos.11633005 and 12073090;the National Key R&D Program of China(Grant No.2020YFC2201400)。

摘　　要：Many evidences show that the Multiple Population(MP)features exist not only in old clusters but also in intermediate-age clusters in the Megallanic Clouds(MCs),which are characterized by star-to-star abundance scatter of several elements,including helium(He).The red giant branch bump(RGBB)’s photometric properties are proved to be related to the variation in helium abundances of the member stars in star clusters.We use the"Modules for Experiments in Stellar Astrophysics"(MESA)stellar evolution code to calculate the evolution sequences of stars along the red giant branch(RGB)with changing helium content.Following the RGB sequences,we then generate a luminosity function of the RGB stars within the grid of input helium abundances,which are compared with the observational data of an intermediate-age MC cluster NGC 1978.

关 键 词：globular clusters:general globular clusters:individual(NGC 1978) stars:abundances stars:Hertzsprung-Russell and C-M diagrams stars:luminosity function 

分 类 号：P152[天文地球—天文学]