Confusing Binaries: The Role of Stellar Binaries in Biasing Disk Properties in the Galactic Center
Confusing Binaries: The Role of Stellar Binaries in Biasing Disk Properties in the Galactic Center
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令人困惑的双星：恒星双星在银河系中心盘特性偏置中的作用
DOI：
10.3847/2041-8213/aaa6bf
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Jessica R. Lu
中科院分区：
文献类型：
--
作者：
S. Naoz;A. Ghez;A. Hees;T. Do;G. Witzel;Jessica R. Lu
银河系中心超大质量黑洞（SMBH）附近的年轻恒星群对星星形成理论提出了一个意想不到的挑战。对这些恒星的运动学测量揭示了一个恒星盘结构（明显的20%盘成员），这为这些神秘的年轻恒星的起源提供了重要线索。然而，许多明显的磁盘属性是很难解释的，包括低磁盘成员分数和高偏心率，因为这个人口的年轻。到目前为止，所有推导这个圆盘性质的努力都是基于一个简单的假设，即GC上的恒星都是单星。然而，恒星双星在我们的银河系中很普遍，最近的调查表明，它们在银河系中心也可能很丰富。在这里，我们表明，在磁盘中的二进制文件可以在很大程度上改变磁盘的表观轨道特性。双星成员的相互运动增加了一个速度分量，这可以与GC中SMBH周围的速度大小相媲美。因此，忽略联星的贡献可能会显着改变推断的恒星的轨道特性。虽然星盘的方向不受影响，但视星盘的2D宽度将增加到约11.°2，与观测到的宽度相似。对于一群以零偏心率绕SMBH轨道运行的恒星，无法解释的双星将产生一个平均为0.23的广泛的视偏心率分布。这与观测到的星盘中恒星的平均离心率是一致的。我们认为，这种高偏心率值，这构成了理论上的挑战，可能是一个人工制品的双星。最后，我们的研究结果表明，实际的磁盘成员可能会显着高于一个推断的观测，忽略了二进制的贡献，减轻了另一个理论挑战。
The population of young stars near the supermassive black hole (SMBH) in the Galactic Center (GC) has presented an unexpected challenge to theories of star formation. Kinematic measurements of these stars have revealed a stellar disk structure (with an apparent 20% disk membership) that has provided important clues regarding the origin of these mysterious young stars. However, many of the apparent disk properties are difficult to explain, including the low disk membership fraction and the high eccentricities given the youth of this population. Thus far, all efforts to derive the properties of this disk have made the simplifying assumption that stars at the GC are single stars. Nevertheless, stellar binaries are prevalent in our Galaxy, and recent investigations suggested that they may also be abundant in the Galactic Center. Here, we show that binaries in the disk can largely alter the apparent orbital properties of the disk. The motion of binary members around each other adds a velocity component, which can be comparable to the magnitude of the velocity around the SMBH in the GC. Thus, neglecting the contribution of binaries can significantly vary the inferred stars’ orbital properties. While the disk orientation is unaffected, the apparent disk’s 2D width will be increased to about 11.°2, similar to the observed width. For a population of stars orbiting the SMBH with zero eccentricity, unaccounted for binaries will create a wide apparent eccentricity distribution with an average of 0.23. This is consistent with the observed average eccentricity of the stars’ in the disk. We suggest that this high eccentricity value, which poses a theoretical challenge, may be an artifact of binary stars. Finally, our results suggest that the actual disk membership might be significantly higher than the one inferred by observations that ignore the contribution of binaries, alleviating another theoretical challenge.
影响因子：
56.9
作者：
H. Sana;S. D. Mink;A. D. Koter;N. Langer;C. Evans;M. Gieles;E. Gosset;R. Izzard;J. L. Bouquin-J.
通讯作者：
H. Sana;S. D. Mink;A. D. Koter;N. Langer;C. Evans;M. Gieles;E. Gosset;R. Izzard;J. L. Bouquin-J.
DOI：
10.1088/0004-637x/708/1/834
发表时间：
2009-08
期刊：
The Astrophysical Journal
影响因子：
--
作者：
H. Bartko;Fabrice Martins;S. Trippe;T. Fritz;R. Genzel;T. Ott;F. Eisenhauer;S. Gillessen;
通讯作者：
H. Bartko;Fabrice Martins;S. Trippe;T. Fritz;R. Genzel;T. Ott;F. Eisenhauer;S. Gillessen;