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Star formation in the remnant clouds associated with OB Associations

与 OB 协会相关的残余云中的恒星形成

基本信息

批准号：
09640322
负责人：
NAKANO Makoto
金额：
$ 1.41万
依托单位：
Oita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640322/
关键词：
Pre-Main Sequence Stars Star Formation Molecular Clouds OB Association

项目摘要

The main body of the molecular cloud has been studied in detail, however, there has been only a little information about the surrounding area including On OB1a, b associations. We have detected more than forty X-ray sources in the On OB1b region, where the activity of star formation is low, by the ASCA satellite. The X-ray luminosities of each source are 1030-1031 erg/s and the average temperature is 4 keV.Eight sources are identified as known low-mass pre-main sequence stars (CTTS), and most of them lie in the field where the Horsehead nebula is located. For other X-ray sources, we have made infrared photometry and showed that their position on the near-infrared two color diagram is consistent that most of them are WTTS.We also found X-ray emission from possible extragalactic sources in this region.We also made statistical analysis of the surface distribution of emission line stars and clustering properties. As the site of star formation outside of the main giant molecular clouds, we … More have studied "remnant clouds" in the Orion region as well. CO observations of the "remnant clouds" including reflection clouds, cometary globules, and bright-rimmed clouds revealed molecular line emission from 60% of the 24 target clouds. Many of them appear associated with the candidates of pre-main sequence stars. These results suggest that the star forming activity is rather low but still cotinueing.Furthermore, we have carried out X-ray observations of another GB association, Mon OB1. Mon OB1 is more distant than On OB1, but one field of ASCA covered the main part of this association. The detailed data analysis is still going on, we have detected twelve X-ray sources. Particularly two X-ray sources coincide well with the cluster of near-infrared sources and dense molecular cloud cores. The peaks of bard X-ray emission of these two sources were identified as NGC 2264 IRS1 and 2, class I sources with intermediate bolometric luminosities. Our X-ray data may provide the important information on the formation of stars with intermediate mass. Less

分子云的主体已被详细研究，然而，只有很少的信息，周围地区，包括对OB 1a，B协会。在星星形成活动较低的OB 1b区域，我们已经用ASCA卫星探测到了40多个X射线源。每个源的X射线光度为1030-1031 erg/s，平均温度为4keV。8个源被确认为已知的低质量主序前星（CTTS），它们大多位于马头星云所在的区域。对其它X射线源进行了红外测光，发现它们在近红外双色图上的位置基本一致，大部分都是WTTS，并在该区域发现了可能的河外源X射线辐射，对辐射线星的表面分布和成团性质进行了统计分析。作为星星形成的场所，我们 ...更多信息也研究了猎户座区域的“残留云”。CO观测的“残余云”，包括反射云，彗星球状，和明亮的边缘云显示分子线发射的24个目标云的60%。它们中的许多似乎与前主序星的候选者有关。这些结果表明，该星团的星星形成活动虽然很低，但仍在继续。此外，我们还对另一个GB星协Mon OB 1进行了X射线观测。Mon OB 1比On OB 1更远，但ASCA的一个领域覆盖了该协会的主要部分。详细的数据分析仍在进行中，我们已经探测到了12个X射线源。特别是两个X射线源与近红外源簇和致密分子云核心吻合得很好。这两个源的硬X射线发射峰被确定为NGC 2264 IRS 1和2，具有中等热光度的I类源。我们的X射线数据可能提供中等质量恒星形成的重要信息。少