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The Research of Massive Star Forming Regions.

大质量恒星形成区域的研究。

基本信息

批准号：
61540188
负责人：
OMODAKA Toshihiro
金额：
$ 0.77万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61540188/
关键词：
Star Formation Massive Star Giant Molecular Cloud HII Regions Bright Rim Proto Stellar Disk Shock Waves 原始星星生成大質量星分子線観測 H【II】領域分子雲 proto-stellar condensation

项目摘要

The study of star formation is a relatively young descipline of the field of astronomy. Though many data to this project now exists, we have not yet produced a viable theory of star formation. Especially for massive star formation, there are many important question which remained unanswered. As the massive star forming region are very far except OMC1, high resolution radio observations are needed to study the dense corse of GMC. Recently high resolution observations are available by using 45m telescope of Nobeyama Radio Observatory. In this project we have observed 5 bright rimmed molecular clouds(NGC281,M17,IC1848,Orion Bright Bar,S140,IC1848) to study the blister model of massive star formation and 5 massive star forming regions to study the evolution of proto massive stellar disk.(W58,W31,W30H,ON1,W33) using 45 m telescope. One frequently cited prescription for a link between molecular clouds and massive star fomation is the blister model of massive star formation, in which massive … More stars form on the surfaces of molecular clouds as a result of external perturbation. For this we observed Orion bright bar. This bar has ideal configuration to study the interaction between HII region and molecular cloud. We found the evidence of shock compressed layer lying parallel to the ionization front. However the apparent density enhancement of 3 in the shocked regions is too small for a radiative shock. In order to explain this discrepancy we proposed a model that the shock compressed region are clumpy or inhomogneous. The observations of M17 also supports this picture. However we can't find the evidence that shocks can compress material enough to trigger star formation.In order to study the evolution of proto stellar disk we observed 5 massive star forming regions. Main results are as follows. 1. In W58 we found a massive proto stellar disk which rotates in a direction parallel to the galactic rotation. Also the velocity gradients of ^<13>CO and HCO^+ emissions suggests differential rotation. 2. Elongated massive structures are found and there are velocity gradient in the direction to the elongation. 3. Every elongated structure has two or three dense cores. 4. Each dense core has a velocity gradient nearly parallel to the elongated structure. We think that this velocity gradient is due to rotation. From these results, we proposed a scenario of the evolution of the proto stellar disk. Less

对恒星形成的研究是天文学领域中一个相对年轻的学科。虽然这个项目现在有很多数据，但我们还没有提出一个可行的恒星形成理论。特别是对于大质量恒星的形成，有许多重要的问题仍未得到解答。由于大质量恒星形成区域离OMC1很远，因此需要高分辨率的射电观测来研究GMC的致密星系。最近利用野山射电天文台的45米望远镜进行了高分辨率的观测。本项目观测了5个明亮边缘分子云（NGC281、M17、IC1848、猎户座亮棒、S140、IC1848），研究了大质量恒星形成的泡罩模型；观测了5个大质量恒星形成区，研究了原大质量恒星盘的演化。（W58,W31,W30H,ON1,W33），使用45米望远镜。关于分子云和大质量恒星形成之间的联系，一个经常被引用的说法是大质量恒星形成的水泡模型，在这种模型中，由于外部扰动，在分子云的表面上形成了更多的大质量恒星。为此我们观察了猎户座亮条。该棒具有研究HII区与分子云相互作用的理想配置。我们发现激波压缩层平行于电离锋的证据。然而，对于辐射激波来说，在激波区域3的表观密度增强太小。为了解释这种差异，我们提出了激波压缩区是块状或不均匀的模型。对M17的观测也支持这一观点。然而，我们无法找到证据表明激波可以压缩物质到足以引发恒星形成。为了研究原恒星盘的演化，我们观测了5个大质量恒星形成区。主要结果如下：1. 在W58中，我们发现了一个巨大的原恒星盘，它的旋转方向与银河系的旋转方向平行。^<13>的CO和HCO^+的速度梯度也表明了不同的旋转。2. 在拉伸方向上存在速度梯度，并发现了块状伸长组织。3. 每一个细长的结构都有两个或三个密集的核心。4. 每个致密岩心的速度梯度几乎与细长结构平行。我们认为这个速度梯度是由旋转引起的。根据这些结果，我们提出了一个原始恒星盘演化的设想。少