A Study of Stellar Pulsations in Eclipsing Binary Stars

在天文学家测量恒星基本属性（如质量、半径、温度和光度）的方法中，有两种方法非常引人注目：一种是密切观察相互绕转的双星，另一种是研究恒星的振荡——星震学——类似于地质学家通过地震学研究地球的方法。维拉诺瓦大学（Villanova University）的这个研究小组试图将这两种技术结合起来，将恒星脉动的物理学原理融入到他们的双星日食计算机代码中，即PHOEBE。该项目将提供机会，通过研究它们在食双星系统中的特性，更好地了解脉动恒星，也反过来，了解脉动如何影响双星。维拉诺瓦大学的天文学小组有让本科生参与研究项目的悠久传统。该项目每年将有两名本科生参与这项研究。两个社区讲习班将为早期职业科学家提供使用PHOEBE的培训，并特别考虑到地理多样性、性别平衡和传统上代表性不足的群体的代表性。研究小组将为维拉诺瓦大学的虚拟现实基础设施CAVE （CAVE自动虚拟环境）和现成的VR耳机提供一个PHOEBE接口。PHOEBE的工作前提是，二元分量表面可以通过三角形网格近似，其中每个三角形都有一组指定的局部量（温度、表面重力、速度、紧急强度等）。这个网格有效地描述了扭曲表面上的物理环境，并解释了我们在双星光曲线中看到的许多影响：由于潮汐相互作用和旋转导致的重力变亮，由于反射、加热和边缘变暗导致的表面亮度变化，日珥（如斑点），以及通过这个项目，恒星脉动。星震学家能够从观测到的光曲线的功率谱中恢复恒星特性的详细信息，这些信息反过来又被用来通过所谓的比例关系推断恒星的基本参数。将恒星脉动纳入PHOEBE将为脉动恒星提供1%或更好的基本恒星参数，从而验证星震标度关系，同时为星震学家的恒星脉动机制模型提供准确的参数。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Among the ways by which astronomers measure fundamental properties of stars (such as mass, radius, temperature, and luminosity), two stand out: by using closely observing binary stars orbiting each other, and by studying oscillations in stars -- asteroseismology -- akin to how geologists study the Earth through seismology. This team at Villanova University seeks to bridge the two techniques by incorporating the physics of stellar pulsations into their eclipsing binary star computer code known as PHOEBE. The project will provide the opportunity to better understand pulsating stars by studying their properties within eclipsing binary systems, and also the other way around, to learn how pulsations influence binarity. The astronomy group at Villanova has a long tradition of involving undergraduates in their research programs. The project will involve two undergrads per year in this research. Two community workshops will provide training in the use of PHOEBE for early career scientists, with special consideration given to geographic diversity, gender balance, and representation from traditionally underrepresented groups. The research team will provide a PHOEBE interface to the virtual reality infrastructure CAVE (Cave Automatic Virtual Environment) at Villanova, and to off-the-shelf VR headsets. PHOEBE works on the premise that binary component surfaces can be approximated by a mesh of triangles where each triangle has an assigned set of local quantities (temperature, surface gravity, velocity, emergent intensity, etc). This mesh effectively describes physical circumstances across distorted surfaces and accounts for many effects we see manifested in binary star light curves: gravity brightening due to tidal interaction and rotation, surface brightness variation due to reflection, heating and limb darkening, prominences such as spots, and, through this project, stellar pulsations. Asteroseismologists are able to recover detailed information on stellar properties from the power spectra of the observed light curves, which are in turn used to deduce fundamental parameters of stars by way of the so-called scaling relations. Incorporating stellar pulsations into PHOEBE will provide fundamental stellar parameters of pulsating stars to 1% or better, thus validating asteroseismic scaling relations while providing asteroseismologists with accurate parameters for their models of stellar pulsation mechanisms.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.