arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0908.0075astro-ph.SR
收藏

HH 212中内结的H2速度结构:不对称性和旋转

The H2 velocity structure of inner knots in HH 212: asymmetries and rotation

S. Correia, H. Zinnecker, S. T. Ridgway, M. J. McCaughrean

摘要:

在2.12 μ m的H2 1-0 S(1)线上获得了高对称原恒星外流HH 212内结的高分辨率R~ 50000长缝光谱,空间分辨率为~0.45角秒。在由此产生的速度分辨率为6 km s-1,多缝定向观测的北部第一个结NK 1清楚地显示双峰线轮廓一致的辐射弓激波或双重(向前和反向)的冲击。相比之下,南部的第一个结SK 1的速度分布仍然是单峰,这表明一个显着较低的射流速度和可能的不同密度变化的射流脉冲在南部流相比,北部流。与半经验分析模型的弓激波排放的比较,使我们能够约束参数,如弓的视线倾斜,弓激波和射流速度为每个流。虽然这个模型没有再现一些功能,但它证实了HH 212双极射流相对两侧之间存在若干动力学和运动学不对称性。这两个节点的位置-速度图表现出复杂的动力学,与弓形激波和/或喷流激波的发射大致一致,这并不排除喷流旋转,尽管HH 212中没有明显的喷流旋转特征。替代的解释,径向速度的变化,这些结,如在射流方向的变化,以及为流量之间的速度不对称性,也被认为是。建议在每个流中存在流速和准直之间的相关性。

英文摘要:

High-resolution R~50 000 long-slit spectroscopy of the inner knots of the highly symmetrical protostellar outflow HH 212 was obtained in the 1-0 S(1) line of H2 at 2.12 micron with a spatial resolution of ~0.45 arcsec. At the resulting velocity resolution of ~6 km s-1, multiple slit oriented observations of the northern first knot NK1 clearly show double-peaked line profiles consistent with either a radiative bow shock or dual (forward and reverse) shocks. In contrast, the velocity distribution of the southern first knot SK1 remains single-peaked, suggesting a significantly lower jet velocity and possibly a different density variation in the jet pulses in the southern flow compared to the northern flow. Comparison with a semi-empirical analytical model of bow shock emission allows us to constrain parameters such as the bow inclination to the line of sight, the bow shock and jet velocities for each flow. Although a few features are not reproduced by this model, it confirms the presence of several dynamical and kinematical asymmetries between opposite sides of the HH 212 bipolar jet. The position-velocity diagrams of both knots exhibit complex dynamics that are broadly consistent with emission from a bow shock and/or jet shock, which does not exclude jet rotation, although a clear signature of jet rotation in HH 212 is missing. Alternative interpretations of the variation of radial velocity across these knots, such as a variation in the jet orientation, as well as for the velocity asymmetries between the flows, are also considered. The presence of a correlation between flow velocity and collimation in each flow is suggested.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑