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arXiv 2102.01352astro-ph.GA
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旋转大质量恒星对星际介质的重元素贡献

Heavy element contributions of rotating massive stars to Interstellar Medium

R. Q. Wu, C. H. Zhu, G. L. Lü, Z. J. Wang, H. L. Liu

摘要:

利用恒星演化程序(恒星天体物理实验模块)计算了大质量恒星通过星风和核心坍缩超新星(CCSN)喷出物到星际介质(ISM)的重元素产额。在我们的模型中,大质量恒星的初始质量($M_{\rm ini}$)取13 ~ 80 $M_\odot$,初始自转速度(V)分别为0、300和500 km/s $^{-1}$,金属丰度分别为[Fe/H] =-3、-2、-1和0.来自恒星风的重元素产额主要受恒星自转的影响,恒星自转通过化学均匀演化改变了恒星表面的化学丰度,提高了质量损失率。我们估计星风可以产生大约$10^{-2}$(对于低金属丰度模型)到几个$M_\odot$(对于低金属丰度和快速旋转模型)质量的重元素产额。CCSN喷出物产生的重元素产额还取决于块状物质的剩余质量,而块状物质的剩余质量主要取决于CO核的质量。我们的模型计算出CCSN喷出物产生的重元素产额可达几个$M_\odot$。与星风相比,CCSN喷出物对ISM中重元素的贡献更大。我们还比较了本文计算的$^{56}$ Ni产额与观测估计值。我们的模型只解释了由暗SNe或正常SNe产生的$^{56}$ Ni质量,其前身质量低于约25 $M_\odot$,并且大大低估了由质量高于约30 $M_\odot$的恒星产生的$^{56}$ Ni质量。

英文摘要:

Employing the the stellar evolution code (Modules for Experiments in Stellar Astrophysics), we calculate yields of heavy elements from massive stars via stellar wind and core-collapse supernovae (CCSN) ejecta to interstellar medium (ISM). In our models, the initial masses ($M_{\rm ini}$) of massive stars are taken from 13 to 80 $M_\odot$, their initial rotational velocities (V) are 0, 300 and 500 km s$^{-1}$, and their metallicities are [Fe/H] = -3, -2, -1, and 0. The yields of heavy elements coming from stellar winds are mainly affected by the stellar rotation which changes the chemical abundances of stellar surfaces via chemically homogeneous evolution, and enhances mass-loss rate. We estimate that the stellar wind can produce heavy element yields of about $10^{-2}$ (for low metallicity models) to several $M_\odot$ (for low metallicity and rapid rotation models) mass. The yields of heavy element produced by CCSN ejecta also depend on the remnant mass of massive mass which is mainly determined by the mass of CO-core. Our models calculate that the yields of heavy elements produced by CCSN ejecta can get up to several $M_\odot$. Compared with stellar wind, CCSN ejecta has a greater contribution to the heavy elements in ISM. We also compare the $^{56}$Ni yields by calculated in this work with observational estimate. Our models only explain the $^{56}$Ni masses produced by faint SNe or normal SNe with progenitor mass lower than about 25 $M_\odot$, and greatly underestimate the $^{56}$Ni masses produced by stars with masses higher than about 30 $M_\odot$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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