The Long-term Evolution of Main-sequence Binaries in DRAGON Simulations
The Long-term Evolution of Main-sequence Binaries in DRAGON Simulations
复制标题
DOI：
10.3847/1538-4365/abcfb8
复制
发表时间：
2020-11
期刊：
影响因子：
--
通讯作者：
Q. Shu;X. Pang;F. F. Dotti-F.;M. Kouwenhoven;M. A. Sedda;R. Spurzem
中科院分区：
文献类型：
--
作者：
Q. Shu;X. Pang;F. F. Dotti-F.;M. Kouwenhoven;M. A. Sedda;R. Spurzem
我们对Dragon模拟中的主序列双星进行了全面的研究，这是第一次对球状星系团的100万粒子直接N体模拟。我们分析了D2-R7-IMF93和D2-R7-IMF01两个Dragon模拟中双星样本的轨道参数，重点分析了它们的长期演化和12Gyr之间的关联。这两个模型具有不同的初始恒星质量函数：Kroupa1993(D1-R7-IMF93)和Kroupa2001(D2-R7-IMF01)，以及不同的初始质量比分布：随机配对(D1-R7-IMF93)和幂定律(D1-R7-IMF93)。一般来说，由于恒星演化，双星群的质量比随着时间的推移而增加，这在D2-R7-IMF01中不那么明显。在D_1-R_7-M_(F93)中，最常见的是质量比为Q_(≈)为0.2的原始双星，其频率始终随Q的增大而线性下降。这两种模型的动力学双星都比原始双星具有更高的偏心率和更大的半长轴。它们优先位于星团的内部。二元轨道参数的长期演化不依赖于初始质量比分布，而是对系统的初始二元分布敏感。当t=12Gyr时，二元组分从径向向外减小，出现质量偏析。在F330W−F814W和NUV−y中，核心和外围的色差分别为0.1mag和0.2mag，这反映了团簇中的双星径向分布和质量偏析。所有快照间隔的原始和动态二进制系统的完整数据集是公开可用的。
We present a comprehensive investigation of main-sequence binaries in the DRAGON simulations, which are the first one-million-particle direct N-body simulations of globular clusters. We analyze the orbital parameters of the binary samples in two of the DRAGON simulations, D1-R7-IMF93 and D2-R7-IMF01, focusing on their secular evolution and correlations up to 12 Gyr. These two models have different initial stellar mass functions: Kroupa 1993 (D1-R7-IMF93) and Kroupa 2001 (D2-R7-IMF01); and different initial mass-ratio distributions: random paring (D1-R7-IMF93) and a power law (D1-R7-IMF93). In general, the mass ratio of a population of binaries increases over time due to stellar evolution, which is less significant in D2-R7-IMF01. In D1-R7-IMF93, primordial binaries with a mass ratio q ≈ 0.2 are most common, and the frequency linearly declines with increasing q at all times. Dynamical binaries of both models have higher eccentricities and larger semimajor axes than primordial binaries. They are preferentially located in the inner part of the star cluster. Secular evolution of binary orbital parameters does not depend on the initial mass-ratio distribution, but is sensitive to the initial binary distribution of the system. At t = 12 Gyr, the binary fraction decreases radially outwards, and mass segregation is present. A color difference of 0.1 mag in F330W − F814W and 0.2 mag in NUV − y between the core and the outskirts of both clusters is seen, which is a reflection of the binary radial distribution and the mass segregation in the cluster. The complete set of data for primordial and dynamical binary systems at all snapshot intervals is made publicly available.