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

天文仪器的最新进展使文科院校的小型天文台能够自动操作望远镜，并利用现代“CCD”（电荷耦合器件）探测器快速准确地测量天体的亮度。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，以这些方式升级他们的卫斯理大学24英寸望远镜。在NSF的资助下，他计划将它们作为本科生的研究和教学工具。PI和他的学生将观察选定的T Tauri和超新星恒星随着时间的推移。金牛座T星被认为是非常年轻的恒星，并且已知它们的变化具有不规则和周期性成分。这种不规则的成分很可能是由落在星星周围的星周盘上的物质产生的。相反，周期性成分很可能是由星星旋转时出现的一个磁“点”和随后从我们的视野中消失所产生的。第二个项目将是监测附近星系中的超新星光。超新星被认为是一个离散的子群的成员，每个子群都有明确的性质，由它们随时间的“光变曲线”决定。这些性质可能与超新星的绝对光度有关。PI将监测超新星的光变曲线，以确定有多少属于这些亚群中的每一个，从而提供有关不同类型的超新星生成演化情景的概率以及这些恒星本身的绝对光度的信息。通过比较观测到的亮度和导出的光度，PI将能够确定超新星的距离，从而确定外部星系的距离。

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.