Collaborative Research: Using Spectroscopy of Light Echoes to Observe the 19th Century Great Eruption of Eta Carinae

这个项目将对19世纪著名的大质量爆发恒星船底座埃塔的大爆发进行详细的光谱研究，目标是在爆发发生160年后发现的光回声。船底座埃塔是一类非终结爆发的原型，这种爆发主导着大质量恒星的质量损失，并与超新星爆发前的剧烈喷发有关，这种喷发会产生宇宙中最明亮的超新星。由于天文摄谱仪在爆发时还没有发明出来，我们关于它爆发的经验信息一直局限于对其视觉亮度的历史记录。然而，我们最近发现的船底二星的光回声提供了一个独特的机会，可以用现代仪器重新观察它，因为19世纪火山喷发发出的光被周围恒星形成区域附近的尘埃云反射回来，现在到达了我们这里。通过观察我们发现的多重光回声，我们将得到19世纪船底座埃塔火山爆发的详细光谱时间序列，包括短暂的增亮事件，峰值前和峰值之间的静止时间，以及持续时间较长的明亮阶段。了解船底二星的三维效应将有助于我们模拟银河系外的事件，因为我们缺乏任何关于几何的空间解析信息。我们将直接测试和完善喷发理论，包括非终点爆炸和超过爱丁顿极限的密集连续驱动风。这项研究也非常及时：它将为当前瞬态观测和对LSST的预期所推动的对爆发瞬态源的快速增长的兴趣提供信息，它将为已知最亮超新星之前的超大质量恒星喷发提供重要线索（在JWST努力在高红移探测它们之前），它将为一些最近提出的船底座埃塔喷发模型提供直接测试。该计划的广泛科学影响有几个方面。它将提供关于一颗著名的大质量恒星及其历史事件的独特和及时的信息，这是理解宇宙中瞬变现象、与非终末瞬变事件有关的爆发和爆炸以及它们在恒星生命和死亡中的作用的基准。此外，我们亦会透过科学发展局公共外联部制作的专业图像和动画，制作一系列由小组成员制作的YouTube短片，向非专业人士讲解计划的主要内容。对于天文学传统上代表性不足的群体，通过参与美国国家科学基金会资助的亚利桑那州与加州理工学院波莫纳分校之间的CAMPARE交流项目，我们将招募少数民族本科生直接参与研究，该项目拟资助的亚利桑那州研究生为女性。

This program will perform a detailed spectroscopic study of the 19th century Great Eruption of the famous eruptive massive star Eta Carinae, by targeting light echoes discovered 160 years after the outburst occurred. Eta Carinae is the prototype for a class of non-terminal eruptions that dominate mass loss in massive stars and have been linked to violent pre-supernova ejections that yield the most luminous supernovae in the universe. Our empirical information about its eruption has been limited to historical accounts of its visual brightness, since the astronomical spectrograph had not yet been invented when the eruption occurred. However, our recent discovery of light echoes from Eta Carinae provides a unique opportunity to get a second look with modern instruments, because light from the 19th century eruption bounced off nearby dust clouds in the surrounding star-forming region, reaching us now. By observing the multiple light echoes we have discovered, we will produce a detailed spectral time-sequence of the 20-yr long 19th century eruption of Eta Carinae, including brief brightening events, quiescent times before and between peaks, and long-duration bright phases. Understanding the 3D effects in Eta Carinae will help us model extragalactic events where we lack any spatially resolved information about geometry. We will directly test and refine theories for the eruption that involve non-terminal explosions and dense continuum-driven winds above the Eddington limit. This study is also quite timely: It will inform a rapidly-growing interest in eruptive transient sources fueled by current transient surveys and anticipation of LSST, it will provide important clues to the eruptions from very massive stars that precede the most luminous supernovae known (in advance of JWST's efforts to detect them at high redshift), and it will provide direct tests of some very recently proposed models for the eruption of Eta Carinae itself.There are several aspects to the broad scientific impact of this program. It will provide unique and timely information about a famous massive star and its historical event that is a benchmark for understanding transient phenomena in the universe, eruptions and explosions associated with non-terminal transient events, and their role in the lives and deaths of stars. Aided by professional graphics and animations generated with the help of the STScI public outreach department, we will also produce a series of YouTube videos of team members explaining key aspects of the project for a non-specialist audience. Concerning traditionally underrepresented groups in astronomy, through participation in the NSF-funded CAMPARE exchange program between Arizona and Cal-Poly Pomona, we will recruit minority undergraduates to be directly engaged in the research, and the Arizona graduate student intended to be funded by this grant is female.