How do Density, Feedback, Gas Dynamics, and Magnetic Fields affect Star Formation within Clusters?

密度、反馈、气体动力学和磁场如何影响星团内的恒星形成？

• 批准号: RGPIN-2022-04516
• 负责人: DiFrancesco, James
• 金额: $ 2.99万
• 依托单位: University of Victoria
• 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=762965
• 关键词: How; do; Density; Feedback; Gas

Understanding the origins of stars is a major undertaking in modern astrophysics. Stars form deep within vast molecular clouds across the Galaxy, as the result of a complex interplay between their gas densities and motions, the local magnetic fields, and energy feedback from nearby young stars on different scales. In particular, most stars, and especially those of higher mass, actually form within embedded clusters, groups of 30-1000+ protostars gravitationally bound to each other and their associated gas. Such environments are complicated by the close proximity of so many nearby protostars that impact their surroundings. Nevertheless, a general understanding of star formation requires a thorough analysis of the physical factors within such environments since they lead to stars of all known mass. Indeed, our Sun and its planetary system arguably formed within such a clustered environment. We propose two projects that delve into the origins of stars within clusters using exciting new observations and techniques. First, we will obtain a full census of embedded clusters found in the molecular clouds nearest to the Sun, using mid-infrared data from the soon-to-be-launched James Webb Space Telescope and submillimetre data from the Atacama Large Millimetre Array that together will reveal clearly their youngest protostar populations. To help us find these objects, we will also develop a new machine learning-based classification algorithm. The resulting numbers will be compared to high-resolution maps of the distributions of gas across nearby clouds obtained using data from the Herschel Space Observatory at far-infrared wavelengths. Indeed, a previous examination of these quantities revealed a strong correlation between them but it must be tested within the most extreme environments of embedded clusters. Second, we will examine the motions of the dense gas and the magnetic fields in the same clusters, specifically the larger filamentary structures in clouds that host them and the smaller ones within them. The line emission from ammonia, a great tracer of dense gas motions, toward many nearby clusters has been already mapped from the Green Bank Telescope, and polarization data, a great tracer of magnetic field direction, from the James Clerk Maxwell Telescope in the same locations will be soon also available. The analysis will be carried out using new techniques that isolate gas flows within filaments. Indeed, the combination of these datasets will enable new connections to be made between gas velocity gradients and magnetic field directions and strengths. Given their common targets, the two projects are complementary and together will make significant contributions to understanding star formation in general. These projects will be the basis of the PhD dissertations of two graduate students, and will help maintain Canada's global leadership in this field over the next five years and beyond.

了解恒星的起源是现代天体物理学的一项重要事业。由于其气体密度和运动，局部磁场和来自附近年轻恒星的能量反馈之间的复杂相互作用，恒星在整个银河系的巨大分子云中形成。特别是，大多数恒星，尤其是较高质量的恒星，实际上在嵌入式簇中形成，30-1000+原始质体在重力相互结合及其相关气体。这些环境由于影响周围环境的许多附近的原恒星的近距离近距离而变得复杂。然而，对恒星形成的一般理解需要对这种环境中的物理因素进行彻底的分析，因为它们导致了所有已知质量的恒星。确实，我们的太阳及其行星系统可以说是在这种聚集的环境中形成的。我们建议使用令人兴奋的新观察和技术来研究群集中恒星的起源的两个项目。首先，我们将使用来自即将发出的詹姆斯·韦伯（James Webb）空间望远镜的中红外数据和来自Atacama大型毫米阵列的imbillimetre数据，从最接近太阳的分子云中发现了完整的嵌入式簇的人口普查，这些数据将清楚地揭示出他们最小的原子群。为了帮助我们找到这些对象，我们还将开发一种基于机器学习的新分类算法。将所得的数字与使用来自Herschel空间天文台在远红外波长的数据获得的气体分布的高分辨率图进行比较。确实，对这些数量的先前检查表明它们之间存在很强的相关性，但必须在嵌入式簇的最极端环境中进行测试。其次，我们将检查同一簇中的密集气体和磁场的运动，特别是云中较大的丝状结构，其中托管它们和其中较小的丝状结构。来自绿色银行望远镜已经映射到了附近许多群集的巨大气体运动的示踪剂，氨的发射量很快就可以很快从同一地点的James Clerk Maxwell望远镜进行绘制。分析将使用新技术进行分离丝中的气流。实际上，这些数据集的组合将使气速梯度和磁场方向和强度之间建立新的连接。鉴于它们的共同目标，这两个项目是互补的，并且将共同为理解恒星形成做出重大贡献。这些项目将是两位研究生的博士学位论文的基础，并将在未来五年及以后保持加拿大在这一领域的全球领导能力。