Periodic Phenomena in Cataclysmic Binaries

AST 0406813帕特森灾难性双星的钟表装置正在生锈。关于这些恒星的大部分信息都是通过它们所显示的周期性来提供给我们的，而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，也许是由于望远镜时间的稀缺（因为一个周期至少需要观察星星做几个周期）。没有系统的努力来保持对这些时钟的足够关注，以确保不断增加的时间基线可用于继续改进对周期及其变化的了解。 哥伦比亚大学的约瑟夫·帕特森博士一直在开发工具，对这种情况产生重大影响。他发现了目前已知的某些类别的大部分激变双星和大约60%的近期轨道周期（通过合作网络）。这包括两个著名的旧激变变星（CV）T Pyx和AM CVn的精确轨道周期，它们在几十年的研究中一直保守着自己的秘密，现在可能会产生关于双星演化方向和速率的基本信息。Paterson博士将利用这个奖项来追踪第二个主要的双星序列，这些双星的光秒数被赶出热平衡，在那里角动量损失扮演着单星演化中熟悉的核燃烧的角色。他已经确定了四个这样的时期保镖明星，他已经学会了如何找到更多。这是研究双星如何结束生命的重要一步。最后，他将重复1984年的研究距离和增长率的简历，为今天的大大扩大名册。在过去的十年里，Patterson博士和他的同事们已经建立了一个全球性的小型测光望远镜网络，CBA，能够以前所未有的彻底性研究周期性现象。这个（主要是）业余天文学家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元素，如果有适当的营养，应该会蓬勃发展，并扩展到灾难性变量的领域之外。这是业余爱好者对发现的传统兴趣与物理学家对导致与理论对抗的实验的传统兴趣的快乐共生。***

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. ***