Magnetic Fields and Carbon Chemistry in Star Forming Regions

恒星形成区域的磁场和碳化学

• 批准号: RGPIN-2021-02495
• 负责人: Plume, Rene
• 金额: $ 1.75万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763067
• 关键词: Magnetic; Fields; Carbon; Chemistry; Star

This proposal focusses on two timely and important questions in modern astrophysics: 1) Which star & planet forming environments form biologically important molecules, and what kinds of chemistries dominate in different regions? 2) How do magnetic fields affect the shape and structure of star forming molecular clouds, and how does this influence the subsequent formation of stars and planets? To address these questions, I request funding to support two long-term research projects. 1) A study of Complex Organic Molecules (COM) vs Carbon Chain Molecules (CCM) in High Mass Star Forming (HMSF) regions Complex molecules have been identified in many different environments in space. While much attention has been given to the astrobiological importance of COMs, CCMs are also biologically important because even simple ring species like c-C3H2 may be key to producing larger biomolecules; such as carbohydrates. While most studies to date have focussed on a few isolated, low mass cores, most stars (including low mass stars) form in HMSF regions. COMs are known to be abundant in hot cores in HMSF regions. CCMs, however, are thought to be deficient in these regions. Therefore, in this project we will embark upon an observational campaign to detect and map a variety of CCMs in a sample of HMSF regions. Modeling of the observations will help us understand the time scales and physical conditions (i.e. density, UV field strength, temperature, etc) that are important in setting the observed abundances in HMSF regions and directly compare this to similar observational and theoretical work for low mass cores. 2) A study of the 3D morphology and strength of large-scale magnetic fields associated with star forming molecular clouds. Studies have shown that magnetic fields can be important in the formation and evolution of molecular clouds. In particular, it has been proposed that a helical magnetic field wrapping around a cloud could stabilize it against gravitational collapse. The existence of such helical fields, however, has lacked observational confirmation. This is mainly because the traditional methods to measure magnetic field strengths in clouds have a number of inherent difficulties. Over the past few years we have created a new and novel technique to measure the line-of-sight magnetic field (Blos) in molecular clouds. Using this technique, we found that Blos was consistent helical fields wrapping around the clouds but, due to limitations in the data, we could not rule out other geometries. In this project we propose to refine our technique and have embarked on a project at the VLA telescope to survey a sample of molecular clouds with greater sensitivity. The goal is to produce highly sensitive, high resolution maps of the 3D magnetic field geometry in molecular clouds with small enough errors that we can confidently determine the magnetic field geometry.

这一建议聚焦于现代天体物理学中两个及时而重要的问题：1)哪些恒星和行星形成的环境形成了具有生物重要性的分子，以及哪些化学物质在不同的区域起主导作用？2)磁场如何影响恒星形成分子云的形状和结构，以及这如何影响随后恒星和行星的形成？为了解决这些问题，我请求为两个长期研究项目提供资金。1)复杂有机分子(COM)与碳链分子(CCM)在高质量恒星形成(HMSF)区域的研究在许多不同的空间环境中发现了复杂分子。虽然COMS的天体生物学重要性得到了很大的关注，但CCM在生物学上也很重要，因为即使是像c-C3H2这样的简单环状物种也可能是产生更大生物分子(如碳水化合物)的关键。虽然到目前为止，大多数研究都集中在少数孤立的低质量核心上，但大多数恒星(包括低质量恒星)都是在HMSF区域形成的。已知的是，在HMSF地区的热核中存在丰富的COMS。然而，CCMS被认为在这些地区是不足的。因此，在这个项目中，我们将开始一项观测活动，以检测和绘制HMSF区域样本中的各种CCM。对观测数据的模拟将有助于我们理解时间尺度和物理条件(即密度、紫外场强、温度等)，它们对设置HMSF区域的观测丰度非常重要，并直接将其与低质量内核的类似观测和理论工作进行比较。2)研究与恒星形成分子云有关的大尺度磁场的三维形态和强度。研究表明，磁场可以在分子云的形成和演化中发挥重要作用。特别是，有人提出，包裹在云层周围的螺旋磁场可以稳定它，使其不受引力崩塌的影响。然而，这种螺旋场的存在缺乏观测证实。这主要是因为测量云中磁场强度的传统方法存在一些固有的困难。在过去的几年里，我们创造了一种新的、新颖的技术来测量分子云中的视线磁场(Blos)。使用这项技术，我们发现水滴是包裹在云层周围的一致螺旋场，但由于数据的限制，我们不能排除其他几何形状。在这个项目中，我们建议改进我们的技术，并在VLA望远镜上开展了一个项目，以更高的灵敏度测量分子云样本。我们的目标是制作高灵敏度、高分辨率的分子云中3D磁场几何图形，误差足够小，我们可以自信地确定磁场几何图形。