Seismological Investigations of Compact Objects

致密物体的地震学研究

• 批准号: 0707381
• 负责人: James Clemens
• 金额: $ 35.67万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-15 至 2012-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0707381&HistoricalAwards=false
• 关键词: Seismological; Investigations; Compact; Objects

For stars made of ordinary gas, stellar seismology offers the opportunity to use resonant mechanical properties to derive astronomically interesting information about stellar interior structure and composition. For white dwarfs seismology offers similar opportunities as well as the chance to learn fundamental physics. For example, it is suspected that the electron degenerate cores of white dwarfs crystallize during cooling, but the calculations that suggest crystallization require observational confirmation. In this project, Dr. Clemens will identify non-radial pulsation modes in ZZ Ceti stars (pulsating white dwarfs). This first step in their seismological analysis will be accomplished through two new methods. For the brighter targets (V 15.5), time-resolved spectroscopy will be obtained with the Goodman spectrograph on the Southern Observatory for Astrophysical Research (SOAR) Telescope. Line profile variations will be used to measure their spherical degree, even at lower signal-to-noise ratios. For the fainter stars, time series photometry on the Goodman Spectrograph or the SOAR Optical Imager will be used to measure the amplitudes of combination modes, which can be used to identify their spherical degree. It is expected that the modes of 10-20 of the most interesting new ZZ Ceti stars discovered by the Sloan Digital Sky Survey will be identified during the three years of this effort.This project will help support a diverse group of graduate and undergraduate students engaged in state-of-the-art astronomical research in University of North Carolina at Chapel Hill's Goodman Laboratory. The Goodman Laboratory specializes in giving students experience in astronomical instrumentation and the training of the next generation of instrument builders is a priority of the community.

对于由普通气体组成的恒星，恒星地震学提供了一个机会，利用共振的力学性质来获得关于恒星内部结构和组成的天文有趣的信息。对于白矮星来说，地震学提供了类似的机会，也提供了学习基础物理学的机会。例如，人们怀疑白矮星的电子简并核心在冷却过程中结晶，但表明结晶的计算需要观测证实。在这个项目中，克莱门斯博士将识别ZZ Ceti恒星(脉动白矮星)中的非径向脉动模式。他们的地震学分析的第一步将通过两种新方法完成。对于较亮的目标(V 15.5)，将使用南方天文台天体物理研究望远镜(SOAR)上的古德曼光谱仪获得时间分辨光谱。即使在较低的信噪比下，也将使用线条轮廓变化来测量它们的球度。对于较暗的恒星，将使用古德曼光谱仪或SOAR光学成像仪上的时间序列光度法来测量组合模式的幅度，这可以用来识别它们的球度。预计斯隆数字巡天所发现的10-20颗最有趣的新ZZ Ceti恒星的模式将在这项工作的三年内被确定。该项目将帮助支持北卡罗来纳大学教堂山古德曼实验室从事最先进天文学研究的不同研究生和本科生群体。古德曼实验室专门为学生提供天文仪器体验，培训下一代仪器建造者是社区的优先事项。