论文标题
微弱种群III超新星在超生物矮星系中形成CEMP星星中的作用
The role of faint population III supernovae in forming CEMP stars in ultra-faint dwarf galaxies
论文作者
论文摘要
CEMP-NO星星，碳增强金属贫困（CEMP）恒星的子集（$ \ rm [C/Fe] \ GEQ0.7 $和$ \ rm [Fe/H] \ Lessim-1 $）在Ultra-Faint Dwarf（UFD）的星系中发现$ m _ {\ ast} \ sim10^3-10^4 $ msun at $ z = 0 $，以及在银河系（MW）的光环中。这些CEMP-NO恒星是局部化石，可能反映出恒星的第一（Pop〜III）和第二（Pop〜II）的特性。然而，宇宙学模拟一直在努力再现已知的CEMP-NO恒星的碳增强水平。在这里，我们提出了隔离的UFD的新宇宙流体动力放大模拟，这些模拟的气体质量分辨率为$ M _ {\ rm GAS} \ SIM60 $ MSUN。我们包括来自Pop〜III微弱的超新星（SNE）的富集，其中$ e _ {\ rm sn} = 0.6 \ times10^{51} $ erg，以了解CEMP-NO Star的起源。我们确认POP〜III和POP〜II恒星主要负责CEMP和C型正常恒星的形成。这项研究的新知识，我们发现观察到的UFD和MW光晕中的大多数CEMP-NO恒星都可以通过Pop〜IIII SNE具有正常的爆炸能量（$ e _ {\ rm sn} = 1.2 \ times10^{51} {51} $ 〜ERG）和pop〜ii富集，但也需要$ cem cem cem cem cem cem。 [c/fe] \ gtrsim2 $，对应于$ \ rm a（c）\ gtrsim6.0 $的绝对碳丰度。此外，我们发现，当我们创建具有高碳比$ \ rm [C/Fe] \大约3-4 $的CEMP-NO星星时，通过采用微弱的SNE，重现具有极高水平的Cemp-No星星，碳含量极高，$ \ rm a（c）\ rm a（c）\ rm a（c）\ 7.0-7.5 $ 5 $ 5 $ 5 $，同时均在halo and the Mes n of mw and the Mw and Mw。
CEMP-no stars, a subset of carbon enhanced metal poor (CEMP) stars ($\rm [C/Fe]\geq0.7$ and $\rm [Fe/H]\lesssim-1$) have been discovered in ultra-faint dwarf (UFD) galaxies, with $M_{\rm vir} \sim 10^8$ Msun and $M_{\ast}\sim10^3-10^4$ Msun at $z=0$, as well as in the halo of the Milky Way (MW). These CEMP-no stars are local fossils that may reflect the properties of the first (Pop~III) and second (Pop~II) generation of stars. However, cosmological simulations have struggled to reproduce the observed level of carbon enhancement of the known CEMP-no stars. Here we present new cosmological hydrodynamic zoom-in simulations of isolated UFDs that achieve a gas mass resolution of $m_{\rm gas}\sim60$ Msun. We include enrichment from Pop~III faint supernovae (SNe), with $ E_{\rm SN}=0.6\times10^{51}$ erg, to understand the origin of CEMP-no stars. We confirm that Pop~III and Pop~II stars are mainly responsible for the formation of CEMP and C-normal stars respectively. New to this study, we find that a majority of CEMP-no stars in the observed UFDs and the MW halo can be explained by Pop~III SNe with normal explosion energy ($ E_{\rm SN}=1.2\times10^{51}$~erg) and Pop~II enrichment, but faint SNe might also be needed to produce CEMP-no stars with $\rm [C/Fe]\gtrsim2$, corresponding to the absolute carbon abundance of $\rm A(C)\gtrsim6.0$. Furthermore, we find that while we create CEMP-no stars with high carbon ratio $\rm [C/Fe]\approx3-4$, by adopting faint SNe, it is still challenging to reproduce CEMP-no stars with extreme level of carbon abundance of $\rm A(C)\approx 7.0-7.5$, observed both in the MW halo and UFDs.
