Collaborative Research: The Importance of Binarity on the Origin of Wolf-Rayet Stars

合作研究：二元性对沃尔夫拉叶星起源的重要性

• 批准号: 2307595
• 负责人: Desmond Hillier
• 金额: $ 12.17万
• 依托单位: University of Pittsburgh
• 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=2307595&HistoricalAwards=false
• 关键词: Collaborative; Research; Importance; Binarity; Origin; Collaborative; Research; Importance; Binarity; Origin

This project is designed to demonstrate how high-mass stars lose their outermost layers, exposing their cores. Such objects are known as Wolf-Rayet (WR) stars. Most of their hydrogen is gone, and they are made up of the products of nuclear burning such as helium, carbon, and oxygen. WR stars are near the ends of their lives and are destined to explode as spectacular supernovae. There are two methods by which these WRs might form. In the first of these, the outer layers are removed by "stellar winds," in which matter is pushed off the star by the pressure of their intense light. In the second method, material is pulled off the star by the gravity of an orbiting companion star. It is likely that some WR stars form one way, while others form the other. The goal of this project is to find what fraction of WR stars is formed by each method. This result will be important scientifically, because these high-mass stars play a vital role in the ecology of the Universe, manufacturing the elements that make up our planet and the life on it. Their intense explosions at the ends of their lives release these elements into space, triggering the formation of the next generation of stars and planets. These observations will also provide summer internship projects for undergraduates. The project includes the construction and free distribution of college-level exercises in astronomy. The investigator team will use three complementary approaches. First, they will measure the luminosities and chemical composition of representative samples of nitrogen-rich Wolf-Rayet stars (WN) and compare these to those predicted by the evolutionary models. Second, the nature of the enigmatic "WN3/O3" stars will be investigated. These are either archetypes of stripped binaries or a missing link between O stars and WRs. Third, they will conduct a systematic survey for O-type stars in the Large and Small Magellanic Clouds. The relative number of O and WR stars as a function of mass (luminosity) is one of the most fundamental diagnostics of the origins of WRs. Together these three programs will put numbers and uncertainties on the fraction of binaries formed by each mechanism. The authors will also construct a high-resolution spectral atlas of 1000 bright stars covering a wide range of spectral types and luminosity classes. This atlas is intended as a heuristic resource available not only for astronomers but also for astronomy students. It will be used in undergraduate lab exercises at Northern Arizona University. These spectra and teaching units will then be made freely available to everyone through a website.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.

该项目旨在证明高质量恒星如何损失其最外层的层，并暴露了核心。这样的物体被称为狼射线（WR）恒星。它们的大部分氢消失了，它们由氦，碳和氧气等核燃烧产物组成。 WR星星靠近他们生命的尽头，注定要像壮观的超新星一样爆炸。这些WR可能形成两种方法。在其中的第一个中，外层被“恒星风”去除，其中物质因其强光的压力将恒星推开。在第二种方法中，通过轨道伴侣恒星的重力将材料从恒星中取出。有些WR恒星可能形成一种方式，而另一些则形成另一种方式。该项目的目的是找到每种方法形成的WR恒星的比例。从科学上讲，这一结果将很重要，因为这些高质量恒星在宇宙的生态学中起着至关重要的作用，制造构成我们星球及其生命的元素。他们在生命的尽头进行的强烈爆炸将这些元素释放到太空中，从而触发了下一代恒星和行星的形成。这些观察结果还将为本科生提供暑期实习项目。该项目包括在天文学中进行大学级练习的建设和自由分发。调查员团队将使用三种互补方法。首先，它们将测量富含氮的狼射线星（WN）的代表性样品的亮度和化学组成，并将其与进化模型预测的样品进行比较。其次，将研究神秘的“ WN3/O3”星的性质。这些要么是剥落的二进制文件的原型，要么是O恒星和WR之间的缺少联系。第三，他们将对大小的麦哲伦云中的O型星进行系统的调查。 O和WR星的相对数量与质量（光度）的函数是WRS起源的最基本诊断之一。这三个程序将加在一起将数字和不确定性放在每个机制形成的二进制文件的一部分上。作者还将构建1000颗明亮恒星的高分辨率光谱地图集，涵盖各种光谱类型和亮度类别。该地图集旨在作为一种启发式资源，不仅适用于天文学家，而且可用于天文学学生。它将用于北亚利桑那大学的本科实验室演习。然后，这些频谱和教学单元将通过网站自由地向所有人免费获得。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估。