RUI: The Hydrodynamics and Observational Signatures of Binary Mergers

RUI：二元合并的流体动力学和观测特征

• 批准号: 1313091
• 负责人: James Lombardi
• 金额: $ 23.13万
• 依托单位: Allegheny College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1313091&HistoricalAwards=false
• 关键词: RUI; Hydrodynamics; Observational; Signatures; Binary

A large variety of interesting astrophysical objects and systems are thought to pass through a contact or semidetached binary stage. The ultimate outcomes of such evolution include exotica such as binary neutron stars, planetary nebulae with double degenerate cores, ultracompact X-ray binaries, and blue stragglers. In a contact binary system, the two components orbit within a larger common envelope and maintain physical contact, while in a semidetached binary, one star gradually accretes mass from a companion overflowing its Roche lobe. In either case, one or both binary components can expand on a stellar evolution timescale, often causing the binary to become unstable and merge. If the binary components have degenerate cores, the cores can separately survive the merger to form systems with binary compact objects. Regardless of the parent stars, the merger of a binary can result in so-called mergebursts, characterized by a sudden and drastic observed increase in luminosity and by ejecta streaming away from the merger product. Making use of a smoothed particle hydrodynamics (SPH) code, Starsmasher, we will perform a parameter sweep covering such scenarios, varying both the evolutionary state of the parent stars and the mass ratio. We will determine the conditions under which a binary merges, and we will study carefully the dynamics and observable characteristics of the merger and merger product, including its light curve, continuum spectrum, and outflow velocity. Our results will complement binary stellar evolution and population synthesis calculations, they will assist in the interpretation of observations, and they will help explain the formation channels of numerous exotic objects, including specific examples such as V1309 Sco.This project represents an opportunity to foster a connection between researchers at Allegheny College and RIT. The proposed project will provide a valuable research focus for undergraduates at Allegheny. Undergraduates, often grappling with career plans, certainly will benefit from early exposure to intercollegiate collaboration and from building a solid foundation in computational methods, an area with broad applications. Based on his experience with Allegheny College students and their career trajectories, the PI expects that this project will equip them well for success in graduate school and in technically oriented careers. In addition, through the PI's teaching and outreach efforts, the project proposed here has the potential to reach a wide range of people and raise the scientific literacy of both local and national audiences.

许多有趣的天体和系统都被认为经历了接触或半接触的双星阶段。这种演化的最终结果包括奇异的，如双中子星，具有双简并核心的行星状星云，超紧凑X射线双星和蓝离散星。在接触双星系统中，两个组成部分在一个更大的共同包层内运行并保持物理接触，而在半分离双星系统中，一颗星星逐渐从溢出其罗氏瓣的伴星吸积质量。在任何一种情况下，一个或两个双星组件都可以在恒星演化的时间尺度上膨胀，通常会导致双星变得不稳定并合并。如果二进制组件具有退化核，则核可以单独地在合并中存活以形成具有二进制紧凑对象的系统。无论母星是什么，双星的合并都会导致所谓的合并爆发，其特征是观测到的光度突然急剧增加，并从合并产物中喷出。利用平滑粒子流体动力学（SPH）的代码，Starsmasher，我们将执行一个参数扫描覆盖这样的场景，不同的演化状态的母星和质量比。我们将确定条件下的合并，我们将仔细研究合并和合并产品的动力学和可观察到的特征，包括它的光变曲线，连续光谱，和流出速度。我们的研究结果将补充双星演化和人口合成计算，他们将有助于解释观测，他们将有助于解释许多外来物体的形成渠道，包括具体的例子，如V1309 Sco。拟议的项目将提供一个有价值的研究重点在阿勒格尼的本科生。本科生，往往与职业规划的斗争，肯定会受益于早期接触到校际合作，并建立一个坚实的基础，在计算方法，一个领域具有广泛的应用。根据他与阿勒格尼学院学生打交道的经验及其职业轨迹，PI预计该项目将为他们在研究生院和技术导向职业中取得成功做好准备。此外，通过PI的教学和推广工作，这里建议的项目有可能接触到广泛的人群，提高当地和国家受众的科学素养。