An Approach to Search for the Proto-Star Forming Regions

本研究利用45米望远镜和NRO干涉仪观测了与W58、W31、ONI、W33和W30 H有关的分子云，研究了高质量和低质量星星的形成机制。我们的观测揭示了分子云中不同大小的团簇结构。这表明，由于引力坍缩而在巨大分子云中形成的致密核心继续破碎，最终坍缩成星星。这表明了等级制度的分裂。然而，粒度分布似乎不是连续的，而是离散的，粒度比为1：5。这些结果与云湍流分级碎裂的结论不一致。另一项研究是研究低质量星星的形成。毫无疑问，太阳系诞生于50亿年前围绕太阳的气体和尘埃盘。最近的红外观测表明，年轻的恒星有尘埃盘， ...更多信息 0.001至1 Mo的ass（Beckwith等人，1990）。具有尘埃盘的金牛T星的年龄在10^5到10^8年之间。现在有两种太阳系形成的模型，一种是太阳系。例如，卡梅隆的模式（1978）和京都模式（1975）。根据京都模型，星云气体必须保留到天王星形成（10^8年）。所以我们有可能找到这些金牛T星的太阳星云气体。在上述两种模型下，通过求解传输方程计算了原太阳星云的CO辐射。计算的天线温度足够高，可以用野边山45米望远镜探测到。我们对金牛座暗云中的12颗T-Tauri星和离太阳最近的3颗Vega型星进行了CO J=1-0分子线发射观测。金牛座T星主要是太阳质量的恒星，年龄在10^5到10^8年之间，织女星型恒星位于主序中。我们无法探测到所有我们尝试过的恒星的星云气体。我们的灵敏度不足以检测T-Tauri恒星的气体，因为条件。但对于织女星型恒星来说，它足以探测到星云气体是否存在。由此可见，对于具有尘埃盘的主序星，星云气体是不存在的。少

In this research we have studied the high and low mass star formation mechanisms.In order to study massive star formation we have observed the molecular cloud associated with W58, W31, ONI, W33 and W30H by using the 45 m telescope and NRO interferometer. Our observations revealed the clumpy structure with various size in the molecular cloud. This suggests that the dense cores formed in the giant molecular cloud due to the gravitational collapses proceed to fragment and finally collapse into star. This suggests the hierarchical fragmentation. However size distribution doesn't seem to be continuous but discrete with the ratio of 1 to 5 in size. These results are not consistent with the hierarchical fragmentation by cloud turbulence.Another research is to study the low mass star formation. There is little doubt that the solar system was born from a disk of gas and dust encircling the Sun five billion years ago. Recent infrared observations suggest that young stars have dust disks with a m … More ass of 0.001 to 1 Mo (Beckwith et al. 1990). The T-Tauri stars with dust disk have ages ranging from 10^5 to 10^8 year. There are now two models of the formation of the solar system, i. e., Cameron's model (1978), and the Kyoto models (1975). According to Kyoto model, the nebular gas must remain until the formation of Uranus (10^8year). So we have a possibility to find the solar nebular gas toward these T-Tauri stars. We calculate the CO emission from the proto-solar nebula by solving transfer equation assuming the above two models. The calculated antenna temperature is sufficiently high and detectable with 45 m telescope at Nobeyama.We made a survey for CO J=1-0 molecular line emission toward 12 T-Tauri stars in the Taurus dark clouds and 3 Vega type stars nearest to the Sun. T-Tauri stars are predominantly solar mass with ages ranging from 10^5 to 10^8 yr and Vega type stars are in main sequence. We could not detect the nebular gas toward all stars we tried. Our sensitivity was not sufficient to detect the gas of T-Tauri stars because of whether condition. However it is enough to detect if the nebula gas were existed for Vega type stars. So it become clear that the nebula gas is not existed to main sequence stars with dust disk. Less