N2H+ Observations of Molecular Cloud Cores in Taurus
N2H+ Observations of Molecular Cloud Cores in Taurus
复制标题
金牛座分子云核心的 N2H 观测
DOI：
10.1086/382862
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Y. Sekimoto
中科院分区：
文献类型：
--
作者：
K. Tatematsu;T. Umemoto;R. Kandori;Y. Sekimoto
报道了用Nobeama 45m射电望远镜对金牛座分子云核进行的N2H+观测。我们将有年轻恒星的核心与没有年轻恒星的核心进行比较。核心半径、线宽和核心质量的差异很小。在这两种情况下，线宽都是由热运动主导的。N2H+图显示，没有恒星的核心和有恒星的核心之间的强度分布没有太大差异。这与之前在H13CO+中得到的金牛座分子云核的结果相反。这种差异的一个可能解释是无星核中H13CO+的更大程度的耗尽。我们用表面(外部)压力的“临界压力”来研究分子云核的物理状态。在这一分析中，没有恒星的核心和有恒星的核心之间没有系统的区别。两者都离临界均衡状态不远。我们认为，热支持占主导地位的分子云核通过保持接近临界平衡状态向恒星形成演化。这一结果与中等质量恒星形成区OMC-2/3的结果相反，在OMC-2/3区，分子云核通过降低临界压力(耗散湍流)而演化。我们研究了积分光强的径向分布。带有恒星的核心具有浅的(-1.8到-1.6)幂定律密度分布。
N2H+ observations of molecular cloud cores in Taurus with the Nobeyama 45 m radio telescope are reported. We compare cores with young stars to cores without young stars. The differences in core radius, line width, and core mass are small. Line width is dominated by thermal motions in both cases. N2H+ maps show that the intensity distribution does not differ much between cores without stars and those with stars. This is in contrast to the result previously obtained in H13CO+ toward Taurus molecular cloud cores. A larger degree of depletion of H13CO+ in starless cores is one possible explanation for this difference. We studied the physical state of molecular cloud cores in terms of "critical pressure" for the surface (external) pressure. There is no systematic difference between starless cores and cores with stars in this analysis. Both are not far from the critical equilibrium state. We suggest that molecular cloud cores in which thermal support dominates evolve toward star formation by keeping close to the critical equilibrium state. This result is in contrast to that obtained in the intermediate-mass star-forming region OMC-2/3, where molecular cloud cores evolve by decreasing the critical pressure (dissipating turbulence). We investigate the radial distribution of the integrated intensity. Cores with stars are found to have shallow (-1.8 to -1.6) power-law density profiles.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell