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他们的望远镜，并用现代的ccd(带电耦合装置)探测器快速而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NSF的奖励，以这些方式升级了他们的卫斯理大学24英寸望远镜。在NSF的这笔拨款中，他计划将它们用作本科生的研究和教学工具。少年派和他的学生将随着时间的推移观察选定的金牛座和超新星。金牛座T星被认为非常年轻，而且已知它们的变化性既有不规则的组成部分，也有周期性的成分。这种不规则的成分很可能是由物质坠落到恒星周围的恒星圆盘上而产生的。相比之下，周期分量很可能是由于恒星自转时从我们的视野中出现和随后消失的磁性“黑子”而产生的。第二个项目将是监测附近星系中的超新星光。众所周知，超新星是一些离散的子群的成员，每个子群都有明确的性质，由它们随时间变化的“光曲线”来确定。这些性质可能与超新星的绝对光度有关。PI将监测超新星的光曲线，以确定有多少属于这些亚群，从而提供关于不同类型的超新星产生演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.