Twin Jets and Close Binary Formation
Twin Jets and Close Binary Formation
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DOI：
10.3847/2041-8213/ab9d86
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发表时间：
2020-06
期刊：
影响因子：
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通讯作者：
Yusuke Saiki;M. Machida
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文献类型：
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作者：
Yusuke Saiki;M. Machida
利用三维电阻磁流体力学模拟研究了一个紧密双星系统的形成。从恒星前云开始，云的演化被计算到原恒星形成后约400年。碎片发生在引力坍缩的星云中，两块碎片演化成原恒星。原恒星相互绕转，形成一个原双星系统。从环绕两颗原恒星的双星流中出现了广角低速流出，而每颗原恒星偶尔会驱动高速喷流。因此，两个高速射流被低速环双子星流出物包围。喷流的速度超过了100。虽然喷流具有准直结构，但由于双星轨道运动，它们在小尺度上是向后摆动的，在大尺度上是纠缠的。每颗原恒星周围也会出现一个星周盘。在主吸积早期，双星轨道复杂，双星间距小于30 au。首次在数值模拟中再现了最近用大型望远镜观测到的原双星系统的所有特征。
The formation of a close binary system is investigated using a three-dimensional resistive magnetohydrodynamic simulation. Starting from a prestellar cloud, the cloud evolution is calculated until ∼400 yr after protostar formation. Fragmentation occurs in the gravitationally collapsing cloud, and two fragments evolve into protostars. The protostars orbit each other and a protobinary system appears. A wide-angle low-velocity outflow emerges from the circumbinary streams that enclose two protostars, while each protostar episodically drives high-velocity jets. Thus, the two high-velocity jets are surrounded by the low-velocity circumbinary outflow. The speed of the jets exceeds ≳100 . Although the jets have a collimated structure, they are swung back on the small scale and are tangled at the large scale due to the binary orbital motion. A circumstellar disk also appears around each protostar. In the early main accretion phase, the binary orbit is complicated, while the binary separation is within <30 au. For the first time, all the characteristics of protobinary systems recently observed with large telescopes are reproduced in a numerical simulation.