A High Dynamic Range Polarimetric Survey of Circumstellar Disks with Adaptive Optics

AST0206351PI关闭目前，我们对恒星周盘中的尘埃的大部分了解间接地来自未分辨的观测(即，在空间上混淆了来自盘和恒星的光的观测)，这些观测很少或根本没有关于盘正在经历的形态和物理过程的信息。中央星光和从圆盘散射的光之间的高对比度构成了一个困难的技术挑战，到目前为止，这阻碍了对大量圆盘的有效分辨检测。研究人员将利用该小组开发的一种新的高动态范围成像技术(自适应光学辅助Wollaston偏振技术)，该技术对从圆盘散射的偏振光高度敏感(消除了来自恒星的污染的未偏振热发射)，创建了一个数据库，其中包含60个高角分辨率、高灵敏度的对年轻恒星周围恒星周围的恒星圆盘的偏振观测，这些观测来自不同的附近恒星形成区域，这些区域的年龄范围为100-1亿年。这些数据将在亚利桑那大学经验丰富和知识渊博的恒星形成小组的帮助下进行专业分析，以从偏振数据中提取物理盘参数，如盘倾角、标度高度、径向范围、密度估计和尘埃尺寸分布。有了这一新的丰富的信息，关于恒星周盘与其环境之间的关系的问题可能会得到解答，例如母星质量、伴星的影响以及行星形成的初始条件。该项目还包括在新的亚利桑那大学近红外相机中调试一个双成像偏振器，以配合目前正在为霍普金斯山上6.5米望远镜开发的采用光学系统。***

AST 0206351PI CloseCurrently, the bulk of our understanding of dust in circumstellar disks comes indirectly through unresolved observations (i.e. observations that spatially confuse light from the disk and the star) where there is little or no information as to the morphological and physical processes that the disks are undergoing. The high contrast between the central starlight and the light scattered from the disk poses a difficult technical challenge, and, until now, this has prevented the efficient resolved detection of large numbers of disks. The investigators will take advantage of a novel high-dynamic range imaging technique (Adaptive Optics aided Wollaston polarimetry), highly sensitive to the polarized light scattered from a disk (eliminating the contaminating unpolarized thermal emission from the star), developed by the group, to create a database of 60 high angular resolution, high sensitivity polarimetric observations of circumstellar disks around young stars from a variety of nearby star forming regions equally sampled over the age range of 100,000 -100,000,000 years. This data will be expertly analyzed with help from the experienced and knowledgeable star formation group at the University of Arizona to extract physical disk parameters from the polarimetric data, such as the disk inclination, scale height, radial extent, density estimates, and dust size distribution. With this new wealth of information, questions regarding the relationship between circumstellar disks and their environment, for example the parent star mass, the effects of a companion star, and the initial conditions for planetary formation, may be answered. This project also includes the commissioning of a dual imaging polarimeter in the new University of Arizona near-infrared camera, to work in tandem with the adoptive optics system currently being developed for the 6.5 meter telescope on Mount Hopkins. ***