The Role of Magnetic Fields in Forming Stars, Disks, and Planets

磁场在恒星、圆盘和行星形成中的作用

• 批准号: RGPIN-2020-03981
• 负责人: Sadavoy, Sarah
• 金额: $ 2.4万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=739604
• 关键词: Role; Magnetic; Fields; Forming; Stars

Star formation plays a pivotal role in most aspects of astronomy, from the formation and evolution of galaxies to the birth of planets and the origins of life. The physics behind star formation and, in particular, the critical role of magnetic fields in this process is poorly understood. There are relatively few observational constraints on magnetic fields because they are difficult to observe directly. Magnetic fields are generally inferred from polarized emission from interstellar dust grains, but these studies are hampered by unknown dust properties and confusion with non-magnetic signatures. Using a combination of new technologies and new data analysis techniques, my research team will circumvent these limitations to more reliably probe the role of magnetic fields in the formation of stars and planets. First, my team will use multi-wavelength synergy between the James Clerk Maxwell Telescope (JCMT) and Statospheric Observatory for Infrared Astronomy (SOFIA) to infer magnetic fields for different dust populations traced by these telescopes. Theoretical studies predict that polarization signatures vary with dust grain size. Over 10 nearby star-forming clouds have or will have observations from both facilities from large surveys (of which I am a member). With these data, my team will lead the data analyses to test theoretical predictions by measuring magnetic field strengths and dust evolution across several star-forming clouds. Confirmation of these predictions will enable a deeper understanding of both dust and magnetic fields in clouds, whereas a contradiction would indicate that current dust models are wrong. Second, my team will use high-resolution dust polarization observations from the Atacama Large Millimeter Array (ALMA) to trace magnetic fields down to scales of circumstellar disks around young stars (~ 10 AU), where planets form. Recent results from ALMA have shown that polarization signatures in disks can be dominated by non-magnetic mechanisms. To constrain these non-magnetic signatures, my team will use archival and new ALMA data, including data from a polarization survey that I led, to model disk properties and the non-magnetic polarization mechanisms. This project will test theoretical predictions of disk formation and provide robust constraints on dust sizes in disks, connecting disk properties to the onset of planet formation. In summary, recent advances in polarimetry provide the opportunity to probe dust polarization from large clouds to small planet-forming disks. By exploiting new detectors, my research team will circumvent current limitations in using dust polarization to infer magnetic field properties. We will bridge magnetic fields from clouds to disks and determine how they support clouds against fragmentation, support dense cores in clouds against collapse into protostars, and suppress the formation of disks. These outcomes directly affect the types of stars and planets produced during the star formation process.

星星的形成在天文学的大多数方面都起着举足轻重的作用，从星系的形成和演化到行星的诞生和生命的起源。星星形成背后的物理学，特别是磁场在这一过程中的关键作用，人们知之甚少。磁场的观测限制相对较少，因为它们很难直接观测。磁场通常是从星际尘埃颗粒的偏振发射中推断出来的，但这些研究受到未知的尘埃特性和与非磁性特征混淆的阻碍。利用新技术和新数据分析技术的结合，我的研究团队将绕过这些限制，更可靠地探测磁场在恒星和行星形成中的作用。首先，我的团队将利用詹姆斯·克拉克麦克斯韦望远镜（JCMT）和平流层红外天文台（索菲亚）之间的多波长协同作用来推断这些望远镜追踪的不同尘埃群的磁场。理论研究预测，偏振信号随尘埃颗粒大小而变化。超过10个附近的恒星形成云已经或将要从两个大型调查（我是其中的一员）的设施进行观测。有了这些数据，我的团队将领导数据分析，通过测量几个恒星形成云的磁场强度和尘埃演化来测试理论预测。这些预测的证实将使人们能够更深入地了解云中的尘埃和磁场，而矛盾则表明目前的尘埃模型是错误的。第二，我的团队将使用阿塔卡马大型毫米波阵列（阿尔马）的高分辨率尘埃偏振观测来追踪年轻恒星（约10 Au）周围的星周盘尺度的磁场，行星形成。阿尔马最近的结果表明，在磁盘的极化签名可以由非磁性机制。为了限制这些非磁性特征，我的团队将使用档案和新的阿尔马数据，包括我领导的极化调查的数据，来模拟磁盘属性和非磁性极化机制。该项目将测试盘形成的理论预测，并提供对盘中尘埃大小的强大约束，将盘的特性与行星形成的开始联系起来。总之，偏振测量的最新进展提供了从大云到小行星形成盘探测尘埃偏振的机会。通过开发新的探测器，我的研究团队将绕过目前使用尘埃极化来推断磁场特性的限制。我们将搭建从云到磁盘的磁场桥梁，并确定它们如何支持云防止碎片化，支持云中的致密核心防止坍缩成原恒星，并抑制磁盘的形成。这些结果直接影响到在星星形成过程中产生的恒星和行星的类型。