1% accuracy in fundamental stellar parameters? Not without an extensive redesign of eclipsing binary models.

1%%20准确度%20in%20基本%20stellar%20参数？%20Not%20没有%20an%20广泛%20重新设计%20of%20eclipsing%20binary%20模型。

• 批准号: 1517474
• 负责人: Andrej Prsa
• 金额: $ 30万
• 依托单位: Villanova University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2019-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1517474&HistoricalAwards=false
• 关键词: accuracy; fundamental; stellar; parameters; without

Eclipsing binary stars can be used to determine the radius and mass of stars by relying on simple geometry and well understood laws of physics. Observations obtained over the last decade have greatly improved in accuracy, so the theoretical models used to interpret these data require substantial revision. This project identifies the aspects of theoretical models in need of revision and proposes a path to update the models. This will enable accurate (within 1%) measurements of stellar masses and radii. Precise determination of fundamental stellar properties is critical to many branches of astrophysics, from studying the life cycles of stars to determining distances throughout the universe. The advances in modelling approaches and classification are applicable to many problems in astronomy, physics, engineering, and applied mathematics. Conducting this program at a primarily undergraduate institution will provide opportunities undergraduate students learn modern research tools and techniques.The investigators will develop the following improvements to their eclipsing binary modelling codes: (a) optimize stellar surface discretization to mitigate systematics in distorted systems and to be able to model more complicated structures such as accretion disks; (b) systematically treat Doppler boosting for all modelled binaries; (c) devise a numerical framework for the Generalized Roche Potential that will allow for tilted spin axes of components to the orbital axis; (d) rigorously treat multiple body systems, predicting eclipse timing variations, tertiary eclipses, dynamical interactions of extended bodies, and other related phenomena; (e) revise the limb darkening treatment to resolve the ingress/egress fitting problems and, consequently, eliminate systematics from the determination of stellar radii; (f) implement a new morphological classification scheme based on modern embedding algorithms; (g) provide a new formalism for statistical error estimates using Markov Chain Monte Carlo methods and Bayesian inference to resolve a long-standing issue of underestimated parameter errors; (h) account for finite integration time corrections; and (i) write a back-end in python that will allow code parallelization in high performance computing and make it available to the broader astronomical community.

食双星可以依靠简单的几何学和众所周知的物理定律来确定恒星的半径和质量。过去十年中获得的观测数据在精度上有了很大提高，因此用来解释这些数据的理论模型需要进行实质性的修改。该项目确定了需要修改的理论模型的方面，并提出了更新模型的途径。这将使恒星质量和半径的精确测量(在1%以内)成为可能。精确确定恒星的基本性质对天体物理学的许多分支至关重要，从研究恒星的生命周期到确定整个宇宙的距离。建模方法和分类方面的进展适用于天文学、物理学、工程学和应用数学中的许多问题。在一个以本科为主的机构进行这个项目将为本科生提供学习现代研究工具和技术的机会。研究人员将对他们的日食双星模型代码进行以下改进：(A)优化恒星表面离散化，以减轻扭曲系统中的系统学，并能够模拟更复杂的结构，如吸积盘；(B)系统地处理所有建模的双星系统的多普勒助推；(C)为广义罗氏势能设计一个数值框架，允许分量的自旋轴倾斜到轨道轴；(D)严格处理多体系统，预测日食时间变化、第三次日食、扩展天体的动力学相互作用，以及其他相关现象；(E)修订肢体变暗处理，以解决进出口拟合问题，从而消除确定恒星半径的系统学问题；(F)以现代嵌入算法为基础，实施新的形态分类办法；(G)利用马尔科夫链蒙特卡罗方法和贝叶斯推理，为统计误差估计提供新的公式，以解决长期低估的参数误差问题；(H)考虑有限积分时间修正；以及(I)用巨蟒编写后端程序，以便在高性能计算中实现代码并行化，并使其可供更广泛的天文学团体使用。