Collaborative Research: Tracing the Spectropolarimetric History of Circumstellar Structures from High-Mass Stars through Supernovae

虽然他们的领域一度被认为是相当了解的，但大质量恒星界的天文学家现在面临着许多关于恒星质量损失的非球形特征的新的和基本的问题。风团的性质和范围仍然是一个未解决的问题；最近的研究表明，由于这种团块性，O星的质量损失率应该向下修正一个数量级或更多。此外，越来越多的证据表明，磁场可以以意想不到的方式影响热星风中质量损失的几何形状。恒星旋转对一些主序和后主序大质量恒星周围的结构和盘形成的影响仍未完全了解。与此同时，对超新星的详细观测表明，与以前认识到的相比，更多的核心坍缩物体与非球状星周环境发生了广泛的相互作用，这种相互作用的特征可能为大质量超新星祖先的质量损失历史提供线索。这个项目是对大质量恒星和超新星的星周介质中的团块和非球面结构的综合研究。在获得高分辨率光谱偏振数据和使用已建立的蒙特卡罗辐射传输代码的激励下，dr。Ignace和Hoffman和他们的团队将在Wolf Rayet、发光的蓝色变星和O型星的随机聚集风中构建可变线和连续极化的模拟；在其他活跃恒星的圆盘和旋转磁层中；在核心坍缩中超新星与周围环境相互作用。他们还将开发算法，使建模代码能够模拟由磁化恒星的星周场产生的塞曼和汉勒效应引起的线偏振。研究人员在辐射传输技术和解释热星风和相互作用超新星的光谱偏振观测方面都有丰富的经验。通过将这些系统的详细3D模型与多波长和偏振数据相结合，目标是更好地理解如何从主序和演化的大质量恒星的观测和核心坍缩超新星的观测中提取质量损失历史。该项目包括一个独特的外展项目，促进科学事业。伊格纳斯和霍夫曼将各自实施创新战略，在各自的社区改善科学教育和扫盲。伊格纳斯博士将与学校辅导员联系，加强阿巴拉契亚地区中学生和高中生的科学教育。霍夫曼博士将与丹佛大学女子学院（University of Denver’s Women’s College）合作，为非传统的女本科生创造进入科学职业“管道”的新切入点。此外，Ignace博士将继续通过东田纳西州立大学和参与REU现场计划监督本科生研究项目。这项为期5年的基金的大部分将用于支持东田纳西州立大学的一名博士后研究员和丹佛大学的一名研究生的培训和专业发展，他们将接受辐射转移理论建模的培训。

Though their field was once thought to be reasonably well-understood, astronomers in the massive-star community are now faced with a number of new and fundamental questions about the non-spherical character of stellar mass loss. The nature and extent of wind clumping remains an unsolved problem; recent studies suggest that due to this clumpiness, O star mass-loss rates should be revised downward by an order of magnitude or more. In addition, a growing body of evidence shows that magnetic fields can influence the geometry of mass loss in hot star winds in unanticipated ways. The effects of stellar rotation on the structure and formation of disks around some main sequence and post-main sequence massive stars are still not fully understood. Meanwhile, detailed observations of supernovae reveal that many more core-collapse objects interact extensively with aspherical circumstellar environments than previously realized, and signatures of this interaction may be mined for clues to the mass-loss histories of massive supernova progenitors. This project is a comprehensive study of clumpy and aspherical structures in the circumstellar media of massive stars and supernovae. Motivated by access to high-resolution spectropolarimetric data and using an established Monte Carlo radiative transfer code, Drs. Ignace and Hoffman, and their team, will construct simulations of variable line and continuum polarization in the stochastically clumped winds of Wolf Rayet, luminous blue variable, and O stars; in the disks and rotating magnetospheres of other active stars; and in core-collapse supernovae interacting with their immediate environments. They will also develop algorithms that will allow the modeling code to simulate line polarization arising from the Zeeman and Hanle effects from the circumstellar fields of magnetized stars. The investigators have broad experience in both radiation transport techniques and interpreting spectropolarimetric observations of hot star winds and interacting supernovae. By confronting detailed 3D models of these systems with multiwavelength and polarimetric data, the goal is a better understanding of how the mass-loss history of main-sequence and evolved massive stars can be extracted from their observation and those of core collapse supernovae. The project includes a unique outreach program, Promoting Careers in Science, through which Drs. Ignace and Hoffman will each implement innovative strategies for improving science education and literacy in their respective communities. Dr. Ignace will reach out to school counselors to enhance science education among Appalachian middle- and high-school students. Dr. Hoffman will partner with the University of Denver's Women's College to create new entry points into the scientific career 'pipeline' for non-traditional female undergraduate students. In addition, Dr. Ignace will continue supervising undergraduate research projects both through East Tennessee State University and through involvement in an REU site program. The bulk of the 5-year funding will go to support the training and professional development of a postdoctoral researcher at East Tennessee State University and a graduate student at the University of Denver who will be trained in the theoretical modeling of radiation transfer.