论文标题
带有多个恒星种群的球形簇形成：单二进制复合方案
Globular cluster formation with multiple stellar populations: A single-binary composite scenario
论文作者
论文摘要
我们讨论了GC形成场景，其中第一代渐近巨型分支（AGB）恒星（AGB）恒星和中间质量近距离二进制（IMCB）弹出气体可以形成第二代（2G）的恒星。场景中的两个关键参数是1G恒星的恒星初始质量函数（IMF）的二进制恒星（F_B）的分数（alpha）。 GC形成的分析和单区模型得出的原理结果如下。对于Alpha <1.8，2G恒星（F_2G）的质量分数可以高于〜0.4，并且不依赖于F_B。 GC与当前质量（M_GC）的初始质量的比例为2至7，具体取决于0.5 <f_b <0.9的alpha。对于广泛的模型参数，1G和2G恒星之间[Na/Fe]的差异可能高达0.7。即使假定IMCB的原始气体不含液体的原始气体，2G恒星的LI丰度也可能与1G一样高。 2G恒星的形成历史显示至少两个峰，这是由于IMCB种群的气体总弹出率两个峰。根据M_GC，F_2G和M_GC之间观察到的相关性可能是由于alpha引起的。 2G形成（〜10^8 yr）的假设长持续时间是可能的，因为可以通过1G恒星和气体云之间的频繁动态相互作用来抑制巨大的恒星形成。
We discuss a GC formation scenario in which the first generation (1G) of single asymptotic giant branch (AGB) stars and intermediate-mass close binaries (IMCBs) eject gas, from which the second generation (2G) of stars can be formed. The two key parameters in the scenario are the fractions of binary stars (f_b) and the slopes (alpha) of the stellar initial mass functions (IMFs) for 1G stars. Principle results derived by analytic and one-zone models of GC formation are as follows. The mass fraction of 2G stars (f_2g) can be higher than ~0.4 for alpha < 1.8 and is not so dependent on f_b. The ratio of the initial mass of a GC to the present-day mass (M_gc) ranges from 2 to 7 depending on alpha for 0.5 < f_b <0.9. The differences in [Na/Fe] between 1G and 2G stars can be as large as 0.7 for a wide range of model parameters. The Li abundances of 2G stars can be as high as those of 1G even if the pristine gas from IMCBs is assumed to be Li-free. Formation histories of 2G stars show at least two peaks owing to two peaks in the total ejection rate of gas from IMCB populations. The observed correlation between f_2g and M_gc can be due to alpha depending on M_gc. The hypothetical long duration of 2G formation (~ 10^8 yr) is possible, because massive star formation can be suppressed through frequent dynamical interaction between 1G stars and gas clouds.
