CCD Photometry of T Tauri Stars and Supernovae at Van Vleck Observatory

天文仪器的最新进展使文理学院的小型天文台能够自动操作望远镜，并使用现代的“CCD”（电荷耦合器件）探测器快速准确地测量天文物体的亮度。在过去的几年里，首席研究员（PI）和他的同事们利用凯克基金会和美国国家科学基金会的奖励，以这些方式升级了卫斯理大学的24英寸望远镜。在这项NSF资助中，他计划将它们作为本科生的综合研究和教学工具。随着时间的推移，PI和他的学生将观察选定的金牛座T和超新星。金牛座T星被认为是非常年轻的，并且已知它们的可变性既有不规则成分，也有周期性成分。不规则成分很可能是由于物质落在恒星周围的星周圆盘上而产生的。相反，周期成分很可能是由于恒星旋转时，一个磁“斑”的出现和随后的消失而产生的。第二个项目将是监测附近星系的超新星光。众所周知，超新星是离散数量的子群的成员，每个子群都有明确的属性，由它们随时间的“光曲线”决定。这些特性可能与超新星的绝对光度有关。PI将监测超新星的光曲线，以确定每个亚群中有多少属于这些亚群，从而提供有关不同类型超新星产生进化情景的概率的信息，以及这些恒星本身的绝对光度。通过比较观测到的亮度和导出的亮度，PI将能够确定到超新星的距离，从而确定到外部星系的距离。

Recent advances in astronomical instrumentation have permitted small observatories in liberal arts colleges to automate the operation of their telescopes and to measure the brightnesses of astronomical objects quickly and accurately with modern "CCD" (Charged Couple Device) detectors. In the last few years the Principal Investigator (PI) and his colleagues have used awards from the Keck Foundation and the NSF to upgrade their Wesleyan University 24-inch telescope in these ways. In this NSF grant he plans to use them as a combined research and teaching tool for undergraduates. The PI and his students will observe selected T Tauri and supernova stars over time. The T Tauri stars are thought to be extremely young, and are known to have both irregular and periodic components to their variability. The irregular component is likely to arise from material falling onto a circumstellar disk around the star. In contrast, the periodic component is likely to be produced by the appearance and subsequent disappearance of a magnetic "spot" from our view as the star rotates. A secondary project will be the monitoring of supernovae light in nearby galaxies. Supernovae are known to be members of a discrete number of subgroups each with well defined properties determined by their "light curve" with time. These properties can be related to the absolute luminosity of the supernova. The PI will monitor supernova light curves in order to determine how many belong to each of these subgroups, thereby providing information on the probability of different types of supernova-generating evolutionary scenarios, as well as the absolute luminosities of these stars themselves. By comparing observed brightnesses with derived luminosities the PI will be able to determine the distance to the supernova and hence the external galaxy.