Fundamental Stellar Parameters from the CHARA Array

该奖项支持佐治亚州立大学的高角分辨率天文学中心(CHARA)。查拉阵列由六个在光学/近红外中工作的1米口径望远镜组成，排列成Y形，提供了从33米到331米长的15条基线。就望远镜的数量和口径尺寸以及基线长度而言，查拉阵列是世界上最强大的同类设备之一。由佐治亚州立大学(GSU)、美国国家科学基金会、W.M.凯克基金会和大卫和露西尔·帕卡德基金会提供资金，查拉阵列已经开展了几个广泛的观测项目，对恒星天体物理学产生了广泛的影响。其中包括测量快速自转恒星Regulus、Alderamin和Vega的扁率和其他物理参数(包括重力变暗)；检查用于校准造父变星周期光度关系的Baade-Wesselink方法；检测Delta Cephei和北极星(两个造父变星)的环绕恒星包层，并表明这些包层的发射必须模拟，以避免Baade-Wesselink方法中的偏差；发现太阳金属度M矮星比类似质量的M矮星大，但金属度较低的M矮星意味着一个额外的不透明度来源，这不包括在当前的模型中；并测量双星12英仙座各组成部分之间的角分离，其分离的精确度为0.05%，从而提高了它们导出质量的准确性。在获奖期间，将实施几个科学计划，继续利用查拉的独特能力。其中包括对较亮恒星的星角直径的测量，精确度优于1%。这将允许在从M到B的温度范围内对恒星大气代码(包括有效温度和亮度分布)进行关键测试，进化恒星也将包括在内，以表征其大气的尺度高度。将测量更多造父变星的脉动，以进一步校准Baade-Wesselink方法。此外，还将描述围绕Be恒星的盘状物质的性质。对于双星，查拉的高角度分辨率将被用来解析光谱双星，这反过来将允许高质量地测量赫茨斯普林格-罗素图上恒星的质量、光度和半径。已知的太阳系外行星系统也将被检查，以确保面对面的双星不会污染样本。对下一代干涉测量科学和技术专家的培训也将继续。Chara正在通过将其成果纳入佐治亚州立大学教授的大型本科课程来提高科学意识。数以千计的公众参观者来到芒特山。威尔逊还将有机会通过在山上查拉展厅的展示互动学习干涉测量原理。威尔逊(也是用于100英寸望远镜的20英尺迈克尔逊恒星干涉仪)。

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).