RUI: An Observational Study of Novae in Differing Stellar Populations

AST-9731641计划将被用来研究附近星系中新星的空间分布和爆发特性。这项研究的长期动机是为了更深入地了解恒星群对紧密双星系统的形成、演化和性质的影响。在紧密的双星系统中，对新星的研究非常适合于这项任务，因为新星是发光的(MV约为-6到-9)，容易识别(由于它们的喷发性质)，而且数量相当多(银河系新星的速率估计为每年几十次)。不幸的是，尽管银河系新星的观测跨越了本世纪的大部分时间，但人们对新星的空间分布和种群知之甚少，特别是在总体上，以及近距离双星。从表面上看，现有的银河系数据表明，新星主要属于一个旧的盘群，但可能存在一个不同的星群II，也可能存在“凸起”新星成分。然而，从银河系的数据中很难确定存在两个不同的新星群体，因为很明显，由于我们在银河系中的位置，这些数据存在严重的偏见。偏差的主要来源是星际吸收，它遮挡了我们观察到的大多数新星，导致了距离的不确定性，从而导致了观测到的相对较小的银河系新星的空间分布的不确定性。要研究新星的数量，并确定种群差异是否会影响它们的爆发特征，最好的方法是测量新星在外部星系的爆发频率、衰减率和空间分布。作为即将开展的研究的一部分，将测量M33、M81星系和M31外盘区域新星的频率和空间分布。除了测量空间分布和新星率外，还将测量M31盘中新星的B波段光曲线，并将其与已发表的凸起新星的光曲线进行比较，以研究由于潜在恒星群的变化而可能存在的任何差异。本项目将有本科生和硕士生参与观测和观测数据的整理。***

AST-9731641 Shfter An observational program will be carried out to study the spatial distribution and outburst properties of novae in nearby galaxies. The long-range motivation of the study is to acquire a deeper understanding of the effect the underlying stellar population has on the formation, evolution, and properties of close binary systems. Among close binary systems, the study of novae are ideally suited to this task because novae are luminous (Mv about -6 to -9), readily identifiable (due to their eruptive nature), and reasonably numerous (the Galactic nova rate is estimated to be several dozen per year). Unfortunately, despite observations of Galactic novae spanning most of this century, little is known about the spatial distribution and population of novae, in particular, and close binaries, in general. Taken at face value, the available Galactic data suggest that novae belong primarily to an old disk population, but that there may exist a distinct Population II, or "bulge" nova component as well. The existence of two distinct populations of novae is difficult to establish from Galactic data, however, as it is clear that these data are heavily biased by virtue of our position within the Galaxy. The major source of bias results from interstellar absorption, which obscures most novae from our view, and causes uncertainty in the distances and thus uncertainty in the spatial distribution of the relatively small fraction of Galactic novae that are observed. The best approach to studying the population of novae, and for establishing whether population differences may affect their outburst characteristics, is to measure the outburst frequency, fade rates, and spatial distribution of novae in external galaxies. As part of the research to be carried out, the frequencies and spatial distributions of novae will be measured for the galaxies M33, M81, and the outer disk regions of M31. In addition to measuring spatial distributions and nova rates, B-band light curves of novae in th e disk of M31 will be measured and compared with published light curves of bulge novae in order to study any differences that may exist due to the variation in the underlying stellar population. There will be undergraduate students and master's degree students involved in the observations and data reduction of the observations in this project. ***