The Physical Properties of Hot and Cool Massive Stars as a Function of Metallicity in the Local Group

这项工作的动机是需要对不同金属丰度的大质量恒星的精确物理特性进行研究，以便了解它们的演化、恒星形成过程以及对星际介质的反馈机制。特别感兴趣的是温度，它在将观测结果（光谱类型和光度）转化为物理性质（有效温度、表面重力、热光度、半径和推断质量）方面起着关键作用。在这个项目中，将对热（30,000至50,000K）主序和冷（3,000至4,000 k）演化（红超巨星）大质量恒星的有效温标进行改进，这将使用高质量的光谱（在冷巨星的情况下加上红外测光）和最新一代的恒星大气模型来完成这两个极端温度。特别重要的是，这些校准将作为金属丰度的函数发展，因此适用于整个本星系群的其他大质量恒星研究。本科生将通过美国国家科学基金会资助的本科生研究经验和麻省理工学院野外营地项目参与这项工作。学生将成为完整的合作者，参与数据采集、分析、写作和在科学会议上展示结果。这项研究也将在通过洛厄尔天文台访客计划和其他场所进行的公开讲座中进行。在此收集的数据一旦被接受发表，也会被公开。

This work here is motivated by the need for accurate physical properties of massive starsof varying metallicity in order to understand their evolution, star formation processes, andfeedback mechanisms into the interstellar medium. Of particular interest is temperature,which plays a key role in transforming observations (spectral type and photometry) intophysical properties (effective temperature, surface gravity, bolometric luminosity, radius,and inferred mass). In this project, an improvement of the effective temperature scales forboth hot (30,000 to 50,000K) main-sequence and cool (3,000 to 4000K) evolved (redsupergiant) massive stars will be undertaken This will be accomplished using high qualityoptical spectra (plus infrared photometry in the case of the cool giants) and the latestgeneration of stellar atmosphere models at both temperature extremes. Of particularimportance is that these calibrations will be developed as a function of metallicity andtherefore applicable to other studies of high mass stars throughout the local group.Undergraduate students will be involved in this work through the NSF sponsoredResearch Experiences for Undergraduates and MIT Field Camp programs. The studentswill be full collaborators and take part in data acquisition, analysis, writing, and thepresentation of results at scientific meetings. This research will also be featured in publictalks given through the Lowell Observatory visitor program and at other venues. The datacollected here will also be made public once accepted for publication.