Global Dynamics of Accretion in High-Mass X-Ray Binary Systems

高质量 X 射线双星系统中吸积的全局动力学

• 批准号: 2308141
• 负责人: John Blondin
• 金额: $ 32.55万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308141&HistoricalAwards=false
• 关键词: Global; Dynamics; Accretion; Mass; Ray

Some of the most spectacular X-ray sources in the sky are High Mass X-ray Binaries (HMXBs). These are systems where a compact object, such as a neutron star or a black hole, rapidly orbits a hot, young, massive star. The gravitational pull of the compact object pulls material from the star which then spirals onto the compact object producing bright X-ray emission. The PI and his team will run computer simulations to better understand how much material falls onto the compact companion vs. how much escapes the gravitational field of the binary and is lost to interstellar space – this quantity is key for understanding how HMXBs evolve. This work will aid the interpretation of current observations of HMXBs by relating observational properties to the mass transfer rate. Much of this research will be done by undergraduates and will be used to introduce a diverse group of young students to astrophysics research. In addition to their research, the students will present their work at the North Carolina Museum of Natural Sciences and work with staff at the Digital Media Lab in the NC State library to create short YouTube videos. The PI will continue to build a series of short (10 minute) video lessons on fluid dynamics and computational physics that help students get started in this kind of research, with more senior students presenting some of the lessons. The investigator will use a new circumbinary gas dynamics code to investigate the global dynamics of mass and angular momentum accretion in HMXBs to connect observations to system parameters relevant to the evolution and classification of these systems. This work will focus both on well-observed systems like Vela X-1 as well as the broad class of systems ranging from Be X-ray binaries to supergiant fast X-ray transients and accreting black hole systems. By coupling together numerical models of the circumstellar gas dynamics (e.g., Roche lobe overflow, acceleration of the tidally enhanced wind from the donor star, X-ray heating and photoionization of the wind) and of the accretion flow (following the gas to small radii while conserving angular momentum), the investigators have developed a circumbinary gas dynamics code that can improve our understanding of the varied properties of HMXBs. This effort will enable simulations of gravitational accretion flows in three dimensions with sufficient detail to qualitatively describe the origin of any dynamical instability and to quantitatively characterize the resulting flux of mass and angular momentum accreted onto the compact companion or lost from the system in a variety of circumstances.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

天空中一些最壮观的 X 射线源是高质量 X 射线双星 (HMXB)，在这些系统中，致密天体（例如中子星或黑洞）快速绕着炽热、年轻的大质量恒星运行。致密天体的引力将恒星的物质拉出，然后恒星旋转到致密天体上，产生明亮的 X 射线发射。 PI 和他的团队将进行计算机模拟，以更好地了解有多少物质落到致密伴星上，以及如何落到其中。很多逃脱该量是理解 HMXB 如何演化的关键，这项工作将通过将观测特性与传质速率联系起来，帮助解释当前对 HMXB 的观测。该项目由本科生完成，将用于向不同的年轻学生群体介绍天体物理学研究。除了他们的研究之外，学生们还将在北卡罗来纳州自然科学博物馆展示他们的作品，并与北卡罗来纳州数字媒体实验室的工作人员一起工作。北卡罗来纳州州立图书馆将继续制作一系列有关流体动力学和计算物理的短视频（10 分钟）课程，帮助学生开始此类研究，并由更多高年级学生演示一些课程。研究人员将使用新的环二元气体动力学代码来研究 HMXB 中质量和角动量吸积的全局动力学，以将观测结果与与这些系统的演化和分类相关的系统参数联系起来。这项工作将重点关注观测良好的系统。像 Vela X-1以及从 Be X 射线双星到超巨快速 X 射线瞬变和吸积黑洞系统等广泛的系统，通过将星周气体动力学的数值模型耦合在一起（例如罗氏瓣溢出、潮汐增强的加速）。来自供体星的风、X射线加热和风的光电离）和吸积流（跟随气体到小半径，同时保持角动量），研究人员开发了一种环二元气体动力学代码可以提高我们对 HMXB 各种特性的理解这项工作将能够在三个维度上模拟重力吸积流，并提供足够的细节来定性描述任何动态不稳定性的起源并定量表征由此产生的质量通量和质量通量。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。