POWRE: Direct Impact Accretion in Interacting Binary Star Systems

POWRE：相互作用的双星系统中的直接撞击吸积

• 批准号: 0074586
• 负责人: Mercedes Richards
• 金额: $ 7.5万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0074586&HistoricalAwards=false
• 关键词: POWRE; Direct; Impact; Accretion; Interacting

AST-0074586RichardsDirect impact accretion in stars occurs in the class of interacting binary star systems known as the Algol-type binary stars. These systems contain a type B-A main sequence star and a cool type F-K giant star or subgiant companion that fills its Roche lobe. In the short-period Algol stars, the gas flow from the cool component makes contact with the surface of the companion in a direct impact. This impact does not occur in the long-period Algols because they are wider and the radius of the mass gainer is relatively small when compared to the separation of the stars in the binary. The accretion structures produced by the direct impact range from a hot spot on the surface of the star to nearly stable accretion disks called accretion annuli. Data using Doppler tomogram observations of these binaries show evidence of Hydrogen-alpha accretion along the predicted gravitational path of the mass transfer stream. Such distinct images are unique among the entire class of interacting binaries because the Algols are in the slow phase of mass transfer and hence provide an opportunity to capture the process of mass transfer in action. Some short-period Algols have stable accretion structures while others are quite variable and they change within an orbital cycle from a stream-like distribution to one which resembles a classical accretion disk. Dr. Richards has studied these accretion structures by means of Hydrogen-alpha (H-alpha) wavelength and ultraviolet spectroscopy observations, Doppler tomography, and hydrodynamic simulations. Recently, Dr. Richards completed a major study of the H-alpha spectroscopic morphologies of 18 Algol-type star systems. Dr. Richards will take academic leave from the University of Virginia to go to the Institute of Advanced Studies for a sabbatical visit. Dr. Richards will be able to work on enhancing the results from the previous research, during the sabbatical period, by using data from similar studies of ultraviolet spectra and the comparison of Doppler tomograms generated at both optical and ultraviolet wavelengths.This project is funded by the Division of Astronomical Sciences and the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate.***

AST-0074586理查兹恒星中的直接碰撞吸积发生在称为大陵型双星的相互作用的双星星星系统中。 这些系统包含一颗B-A型主序星星星和一颗充满洛希叶的冷F-K型巨星星星或次巨星伴星。 在短周期大陵五恒星中，来自冷组分的气体流与伴星的表面直接接触。 这种影响不会发生在长周期的大陵五中，因为它们更宽，质量增加者的半径相对较小，与双星中的恒星分离相比。 直接撞击产生的吸积结构范围从星星表面的热点到称为吸积环的接近稳定的吸积盘。 使用多普勒断层扫描观测这些双星的数据显示氢-α吸积的证据沿着预测的质量转移流的引力路径。 这种独特的图像是独一无二的整个类之间的相互作用的双星，因为阿尔戈尔是在缓慢阶段的质量转移，因此提供了一个机会，捕捉过程中的质量转移的行动。 一些短周期的Algols有稳定的吸积结构，而另一些是相当可变的，它们在一个轨道周期内从流状分布的一个类似于一个经典的吸积盘。 理查兹博士通过氢-α（H-α）波长和紫外光谱观测、多普勒层析成像和流体动力学模拟研究了这些吸积结构。 最近，理查兹博士完成了对18个大陵五型星星系统的H-α光谱形态的主要研究。 理查兹博士将从弗吉尼亚大学休学，前往高级研究所进行休假访问。 理查兹博士将利用类似的紫外光谱研究数据和比较在光学和紫外波长下产生的多普勒断层图，在休假期间致力于加强以前研究的结果，该项目由天文科学司和数学和物理科学局多学科活动办公室资助。