Is there a compact companion orbiting the late O-type binary star HD 164816?
Is there a compact companion orbiting the late O-type binary star HD 164816?
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DOI：
10.1111/j.1365-2966.2012.22011.x
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发表时间：
2012-09
影响因子：
4.8
通讯作者：
L. Trepl;V. Hambaryan;T. Pribulla;N. Tetzlaff;R. Chini;R. Neuhauser;S. Popov;O. Stahl;F. Walter-F.
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文献类型：
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作者：
L. Trepl;V. Hambaryan;T. Pribulla;N. Tetzlaff;R. Chini;R. Neuhauser;S. Popov;O. Stahl;F. Walter-F.
本文对一颗晚O型X射线探测到的光谱双星HD 164816进行了多波长（X射线、γ射线、光学和射电）研究。分析X射线光谱，检查X射线光子到达时间的脉动。此外，新获得的光学光谱监测数据HD 164816。它们得到了来自几次大规模调查的可用无线电数据以及来自其大面积望远镜的费米γ射线数据的补充。我们报告的检测低能量过剩的X射线光谱，可以描述一个简单的吸收黑体模型与温度为1050 eV，以及9.78秒的脉动的X射线源。软X射线过剩，X射线脉动和运动学年龄都与HD 164816的致密天体相一致，比如中子星星。软X射线过量发射区的大小与半径约为7公里的圆形区域一致，这是中子星的典型特征，而其余较硬发射的发射测量（EM）则是晚O型单星或双星的典型特征。如果HD 164816包含一颗诞生于超新星中的中子星星，那么这颗超新星应该是非常近的，应该给系统带来了一次冲击，这与观测结果一致，即星星HD 164816的径向速度与星团的平均径向速度明显不同。此外，我们通过获得3.82 d的轨道周期，在低倾角下明显看到的投影质量m1 sin 3 i = 2.355（69）M <$，m2 sin 3 i = 2.103（62）M <$，证实了HD 164816本身的双星性。
We present a multi-wavelength (X-ray, γ-ray, optical and radio) study of HD 164816, a late O-type X-ray detected spectroscopic binary. X-ray spectra are analysed and the X-ray photon arrival times are checked for pulsation. In addition, newly obtained optical spectroscopic monitoring data on HD 164816 are presented. They are complemented by available radio data from several large-scale surveys as well as the Fermi γ-ray data from its Large Area Telescope. We report the detection of a low energy excess in the X-ray spectrum that can be described by a simple absorbed blackbody model with a temperature of ∼50 eV as well as a 9.78 s pulsation of the X-ray source. The soft X-ray excess, the X-ray pulsation and the kinematical age would all be consistent with a compact object like a neutron star as companion to HD 164816. The size of the soft X-ray excess emitting area is consistent with a circular region with a radius of about 7 km, typical for neutron stars, while the emission measure (EM) of the remaining harder emission is typical for late O-type single or binary stars. If HD 164816 includes a neutron star born in a supernova, this supernova should have been very recent and should have given the system a kick, which is consistent with the observation that the star HD 164816 has a significantly different radial velocity than the cluster mean. In addition we confirm the binarity of HD 164816 itself by obtaining an orbital period of 3.82 d, projected masses m1sin3i = 2.355(69) M⊙, m2sin3i = 2.103(62) M⊙ apparently seen at low inclination angle, determined from high-resolution optical spectra.