论文标题

来自0类原始二进制二进制系统VLA 1623A Alma揭示的Alma二进制二进制系统的未对准双分子流出

Misaligned Twin Molecular Outflows From Class-0 Proto-stellar Binary System VLA 1623A Unveiled by ALMA

论文作者

Hara, Chihomi, Kawabe, Ryohei, Nakamura, Fumitaka, Hirano, Naomi, Takakuwa, Shigehisa, Shimajiri, Yoshito, Kamazaki, Takeshi, Di Francesco, James, Machida, Masahiro N., Tamura, Motohide, Saigo, Kazuya, Matsumoto, Tomoaki

论文摘要

我们介绍了对低质量级别二进制系统的ALMA观察结果,$^{12} $ CO中的Ophiuchus Molecular Cloud中的VLA 1623aab,$^{13} $ CO,以及C $^{18} $ O(2--1)行。我们的$^{12} $ co($ j $ = 2--1)数据显示,VLA 1623流出由双空间重叠的外流/喷气机组成。红移的西北喷气机以1360 $ \ pm $ 10 au的空间时期展示了三个摇摆的循环,对应于180年的时间。在位置速度(PV)图中也发现了类似摇摆的结构,显示速度的幅度约为0.9 km s $^{ - 1} $。摆动的周期和速度幅度都与二进制参数的预期(即轨道周期(460 $ \ pm $ 20 yr)和开普勒速度(2.2 km S $ s $^{ - 1} $)大致一致。我们的$^{13} $ co和c $^{18} $ o图像在两个cm/mm源中揭示了密集气的性质,VLA 1623 -b和-w,及其与流出的关系,并强烈支持先前的解释,这些解释都是震惊的云。因此,双分子流出的驱动来源可能在VLA 1623AAB二元中。据估计,两个分子流出的轴估计在整个天空平面上互相倾斜70 $ \ arcdeg $,这意味着相关的原始磁盘也被$ 70 \ arcdeg $未对准。这种未对准以及在已知的最年轻的原始系统之一中的34个AU的小二元分离,在静止环境中的磁盘碎片模型很难解释。取而代之的是,诸如湍流之类的其他效果可能在错位磁盘中起着作用。

We present the results of ALMA observations toward the low-mass Class-0 binary system, VLA 1623Aab in the Ophiuchus molecular cloud in $^{12}$CO, $^{13}$CO, and C$^{18}$O(2--1) lines. Our $^{12}$CO ($J$=2--1) data reveal that the VLA 1623 outflow consists of twin spatially overlapped outflows/jets. The redshifted northwestern jet exhibits the three cycles of wiggle with a spatial period of 1360$\pm$10 au, corresponding to a time period of 180 yr. The wiggle-like structure is also found in the position-velocity (PV) diagram, showing an amplitude in velocity of about 0.9 km s$^{-1}$. Both the period and the velocity amplitude of the wiggle are roughly consistent with those expected from the binary parameters, i.e., the orbital period (460$\pm$20 yr) and the Keplerian velocity (2.2 km s$^{-1}$). Our $^{13}$CO and C$^{18}$O images reveal the nature of the dense gas in the two cm/mm sources, VLA 1623-B and -W, and its relation to the outflows, and strongly support the previous interpretation that both are shocked cloudlets. The driving sources of the twin molecular outflows are, therefore, likely to be within the VLA 1623Aab binary. The axes of the two molecular outflows are estimated to be inclined by 70$\arcdeg$ from each other across the plane of sky, implying that the associated protostellar disks are also misaligned by $70\arcdeg$. Such a misalignment, together with a small binary separation of 34 au in the one of the youngest protobinary systems known, is difficult to explain by models of disk fragmentation in quiescent environments. Instead, other effects such as turbulence probably play roles in misaligning the disks.

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