The Flattened, Rotating Molecular Gas Core of Protostellar Jet HH 212
The Flattened, Rotating Molecular Gas Core of Protostellar Jet HH 212
复制标题
原恒星喷流 HH 212 的扁平旋转分子气体核心
DOI：
10.1086/319474
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
M. McCaughrean
中科院分区：
文献类型：
--
作者：
J. Wiseman;A. Wootten;H. Zinnecker;M. McCaughrean
最近发现的原恒星喷流被称为HH 212，它是美丽对称的，在激发源区域IRAS 05413-0104的两侧有一系列成对的激波结和弓形激波。我们展示了IRAS 05413-0104分子气体包层的VLA氨图，其中嵌入了原恒星射流源。我们发现，由干涉仪检测到的质量为0.2 M☉的包膜垂直于射流轴，FWHM直径为12,000 AU，轴比为2:1，如NH3（1,1）发射所示。在扁平的盘状地核上有一个大约4-5 km s-1 pc-1的速度梯度，表明它是绕着与喷流对齐的轴旋转的。通量加权平均速度以大致恒定的速度梯度平稳增加。在年轻的（0类）系统中，如HH 212，大量的物质仍然分布在一个大的周围包络层中，因此系统的可观测运动学可能反映了中心不太凝聚的年轻状态，源和中心动力学的模糊。最近的观测表明，这种包层物质的角动量可能是由HH 212喷流中的旋转注入的气体释放的。一束蓝移的发射气体似乎沿着流出的蓝色一侧被扫走，可能在更准直的激波射流轴周围的更宽角度风腔中排列。我们的氨(2,2)/(1,1)比值图表明，这个非常冷的核心在射流源周围的中心冷凝区域被加热到14k。这个边缘的核心和射流系统看起来很年轻，并且深嵌其中。然而，这种环境显然没有破坏原始的对称性和射流的准直。
The recently discovered protostellar jet known as HH 212 is beautifully symmetric, with a series of paired shock knots and bow shocks on either side of the exciting source region IRAS 05413-0104. We present VLA ammonia maps of the IRAS 05413-0104 molecular gas envelope in which the protostellar jet source is embedded. We find that the envelope, with a mass of 0.2 M☉ detected by the interferometer, is flattened perpendicular to the jet axis with an FWHM diameter of 12,000 AU and an axis ratio of 2 : 1, as seen in NH3 (1, 1) emission. There is a velocity gradient of about 4-5 km s-1 pc-1 across the flattened disklike core, suggestive of rotation around an axis aligned with the jet. Flux-weighted mean velocities increase smoothly with a roughly constant velocity gradient. In young (class 0) systems such as HH 212, a significant amount of material is still distributed in a large surrounding envelope, and thus the observable kinematics of the system may reflect the less centrally condensed, youthful state of the source and obscuration of central dynamics. The angular momentum of this envelope material may be released from infalling gas through rotation in the HH 212 jet, as recent observations suggest. A blueshifted wisp or bowl of emitting gas appears to be swept up along the blue side of the outflow, possibly lining the cavity of a wider angle wind around the more collimated shock jet axis. Our ammonia (2, 2)/(1, 1) ratio map indicates that this very cold core is heated to 14 K in a centrally condensed area surrounding the jet source. This edge-on core and jet system appears to be young and deeply embedded. This environment, however, is apparently not disrupting the pristine symmetry and collimation of the jet.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell