Periodic Phenomena in Cataclysmic Binaries

灾难性双星的时钟装置正在生锈。关于这些恒星的大部分信息都是由它们所显示的周期性提供给我们的，物理学的一些关键方面依赖于这些周期的准确性。然而，许多观测者基本上已经放弃了寻找周期，可能是由于望远镜时间的稀缺（因为一个周期最少需要观察一颗恒星的几个周期）。也没有系统的努力对这些时钟进行足够的监视，以确保有一个不断增加的时间基线，以继续提高对周期及其变化的认识。哥伦比亚大学（Columbia University）的约瑟夫·帕特森（Joseph Patterson）博士一直在开发能够对这种情况产生重大影响的工具。他发现了目前已知的某些类型的灾难性双星的很大一部分，以及最近轨道周期的大约60%（通过合作网络）。这包括两个著名的古老的灾难性变星（cv）的精确轨道周期，T Pyx和AM CVn，这两个变星在之前的几十年的研究中一直固执地保守着他们的秘密，现在可能会得到关于双星演化方向和速率的基本信息。帕特森博士将利用这一奖项继续追踪第二个主要的双星序列，这些双星具有被热平衡驱动的轻次级，角动量损失在单星演化中扮演着核燃烧的角色。他已经确定了四颗这样的周期跳跃星，并学会了如何找到更多的周期跳跃星。这是了解双星如何结束生命的重要一步。最后，他将重复1984年关于cv的距离和吸积率的研究，用于今天已经扩展的花名册。这将为星系中cv的寿命、空间密度和尺度高度提供改进的值。在过去的十年里，帕特森博士和他的同事们组建了一个小型光度望远镜的全球网络，即CBA，能够以前所未有的彻底程度研究周期性现象。这个（主要是）业余天文学家组成的网络现在是业余天文学家和专业天文学家研究界面的一个主要组成部分，如果有适当的营养，它应该蓬勃发展，并扩展到灾难性变量的领域之外。业余爱好者对发现的传统兴趣与物理学家对实验的传统兴趣形成了一种愉快的共生关系，从而导致了与理论的对抗。＊＊＊

AST 0406813PattersonThe clockworks of cataclysmic binary stars are rusting away. Most of the information about these stars comes to us courtesy of the periodicities they display, and some critical aspects of the physics rely on the accuracy with which these periods are known. Yet many observers have basically forsaken period-finding, driven perhaps by the scarcity of telescope time (since a period minimally requires watching a star do something for a few cycles). And there is no systematic effort to keep sufficient watch over these clocks to make sure that an ever-increasing time baseline is available to continue improving knowledge of the periods and their changes. Dr. Joseph Patterson, at Columbia University, has been developing the tools to make a strong impact on this situation. He has found a large fraction of certain classes of currently known cataclysmic binary stars and about 60% of recent orbital periods (through a network of collaborations). This includes precise orbital periods for two famous old cataclysmic variables (CVs), T Pyx and AM CVn, which have stubbornly guarded their secret from many decades of prior study, and which will now likely yield fundamental information on the direction and rate of binary evolution. Dr. Paterson will use this award to pursue tracing out a second main sequence of binaries with light secondaries driven out of thermal equilibrium, where angular momentum loss plays the role of nuclear burning familiar in single-star evolution. He has identified four of these period-bouncer stars, and he has learned how to find more. This is a major step towards learning how binary stars end their lives. Finally he will repeat a 1984 study of distances and accretion rates in CVs, for today's much-expanded roster. This will give improved values for the lifetime, space density, and scale height of CVs in the galaxy.Over the last ten years Dr. Patterson and colleagues have assembled a worldwide network of small photometric telescopes, the CBA, able to study periodic phenomena with unprecedented thoroughness. This network of (mostly) amateur astronomers is now a major element in the research interface of amateur and professional astronomers, and, with proper nutrition, should flourish and expand beyond the realm of cataclysmic variables. This has been a happy symbiosis of the amateur's traditional interest in discovery with the physicist's traditional interest in experiments leading to confrontation with theory. ***