Fundamental Stellar Parameters from the CHARA Array

CHARA 阵列的基本恒星参数

• 批准号: 0606958
• 负责人: Harold McAlister
• 金额: $ 70.62万
• 依托单位: Georgia State University Research Foundation, Inc.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0606958&HistoricalAwards=false
• 关键词: Fundamental; Stellar; Parameters; CHARA; Array

This award supports the Georgia State University's Center for High Angular ResolutionAstronomy (CHARA). The CHARA Array consists of six 1-m aperture telescopesoperating in the optical/near infrared and arranged in a Y configuration which provides15 baselines from 33 to 331 meters in length. In terms of the number and aperture size ofits telescopes and the length of its baselines, the CHARA Array is among the mostpowerful facilities of its type in the world.Built with funds provided by Georgia State University (GSU), the NSF, the W.M. KeckFoundation, and the David and Lucile Packard Foundation, the CHARA Array hasundertaken several extensive observational programs with a broad impact on stellarastrophysics. These include measuring the oblateness and other physical parameters(including gravity darkening) for the rapidly rotating stars Regulus, Alderamin, andVega; checking the Baade-Wesselink method for calibrating the Cepheid periodluminosityrelation; detecting the circumstellar envelopes of Delta Cephei and Polaris(two Cepheid variables) and showing that emission from these envelopes must bemodeled to avoid biases in the Baade-Wesselink method; discovering that solarmetallicity M dwarfs are larger than similar mass but lower metallicity M dwarfs whichimplies an additional opacity source not included in current models; and measuring theangular separation between the components of the binary star 12 Persei to an accuracy of0.05% their separation thereby improving the accuracy of their derived masses.During the award period, several science programs will be carried out which continue tocapitalize on CHARA's unique capabilities. These include the measurement of stellarangular diameters of brighter stars to better than 1% accuracy. This will allow the criticaltesting of stellar atmosphere codes (including effective temperatures and brightnessprofiles) at temperatures from M to B. Evolved stars will be included as well tocharacterize the scale heights of their atmospheres. Pulsations of more Cepheid variableswill be measured to further calibrate the Baade-Wesselink method. The properties ofdisks surrounding Be stars will also be characterized. With regard to binaries, CHARA'shigh angular resolution will be used to resolve spectroscopic binaries, which will in turnallow high quality measurements of stellar mass, luminosity, and radius for stars acrossthe Hertzsprung-Russell Diagram. Known extrasolar planetary systems will also beinspected to ensure face-on binaries are not contaminating the samples.The training of the next generation of scientific and technical experts in interferometrywill also continue. CHARA is enhancing scientific awareness through the incorporationof its results into the large undergraduate courses taught at Georgia State. Thousands ofpublic visitors to Mt. Wilson will also have the opportunity to interactively learn theprinciples of interferometry through a display at the CHARA Exhibit Hall on Mt. Wilson(which also houses the 20-foot Michelson Stellar Interferometer used at the 100-inchtelescope).

该奖项支持格鲁吉亚州立大学的高角分辨率天文学中心（CHARA）。CHARA阵列由6个1米口径望远镜组成，在光学/近红外线范围内工作，并以Y形配置排列，提供长度从33米到331米的15条基线。从望远镜的数量和孔径大小以及基线的长度来看，CHARA阵列是世界上同类设施中最强大的。CHARA阵列是由美国国家天文台和大卫和露西尔·帕卡德基金会共同发起的，它已经开展了几项广泛的观测计划，对恒星天体物理学产生了广泛的影响。其中包括测量扁率和其他物理参数（包括重力暗化）;检验用于校准造父变星周期光度关系的Baade-Wesselink方法;探测造父变星Delta和北极星的星周包络（两个造父变星），并表明这些信封的排放必须bemodeled，以避免在Baade-Wesselink方法的偏见;发现太阳金属丰度M矮星比质量相近但金属丰度较低的M矮星大，这意味着有一个额外的不透明度源，而这个不透明度源是目前模型中没有考虑的;测量英仙座星星12的角距，精度为0.05%它们的分离，从而提高其衍生质量的准确性。在获奖期间，将继续利用CHARA的独特能力开展几项科学计划。其中包括测量较亮恒星的星角直径，精度优于1%。这将允许在M到B的温度下对恒星大气代码（包括有效温度和亮度分布）进行临界测试。演化的恒星也将被包括在内，以描述它们大气层的尺度高度。更多造父变星的脉动将被测量，以进一步校准Baade-Wesselink方法。围绕Be星的盘的性质也将被描述。对于双星，CHARA的高角分辨率将被用来分辨光谱双星，这将反过来允许高质量的测量恒星的质量，光度和半径的恒星acrossHertzsprung-Russell图。已知的太阳系外行星系统也将被检查，以确保正面双星不会污染样本。下一代干涉测量科学和技术专家的培训也将继续。CHARA正在通过将其结果纳入格鲁吉亚州立大学的大型本科课程来提高科学意识。数以千计的公众游客到山。威尔逊还将有机会通过在山上的CHARA展览厅的展示互动地学习干涉测量的原理。威尔逊（其中还包括用于100英寸望远镜的20英尺迈克尔逊恒星干涉仪）。