Fundamental Stellar Parameters from the CHARA Array

CHARA 阵列的基本恒星参数

• 批准号: 0307562
• 负责人: Harold McAlister
• 金额: $ 72.79万
• 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: 2003
• 资助国家: 美国
• 起止时间: 2003-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0307562&HistoricalAwards=false
• 关键词: Fundamental; Stellar; Parameters; CHARA; Array

AST 0307562McAlisterGeorgia State University's Center for High Angular Resolution Astronomy (CHARA) operates an interferometric array on Mt. Wilson, California. The CHARA Array consists of six 1-m aperture telescopes arranged in a Y configuration providing 15 baselines from 33 to 331 meters in length. The Array operates in the visible and near-infrared spectral regions with limiting resolutions of 1.6 and 0.4 milli-arcseconds at the K and V bands. In terms of the number and aperture size of its telescopes and the length of its baselines, the CHARA Array is among the most powerful facilities of its type in the world. Built with funds provided by Georgia State University (GSU), the NSF, the W.M. Keck Foundation, and the David and Lucile Packard Foundation, the CHARA Array is poised to undertake extensive observational programs having a broad impact on stellar astrophysics. This award will support these programs primarily by maintaining an adequate scientific, technical and operational staff at the Array site. The core CHARA team has also developed a number of collaborations to more fully exploit the Array's scientific capability. Because of its very high angular resolution and its good sensitivity and UV-plane coverage, the CHARA Array will have unprecedented access to stellar diameter measures for main sequence stars of all temperatures as well as for evolved stars. Accurate low-visibility measurements will characterize atmospheric limb darkening in stars. The sizes and shapes of young stellar objects will be mapped. Pulsations of Cepheid variables and their limb darkening will be measured to directly calibrate this important rung in the cosmic distance ladder. Continuum and molecular band observations will characterize scale heights in the atmospheres of evolved stars. Disks surrounding Be stars and massive outflows from luminous blue variable stars, Wolf-Rayet stars and interacting binaries will be detected and characterized. In the area of binary star studies, the Array will eliminate the classical problem of non-overlapping selection effects among the various techniques for discovering binary stars and measuring their orbital motions. It will resolve the majority of the spectroscopic binaries accessible to it, providing measurements of stellar mass, luminosity and radius for stars broadly distributed throughout the HR diagram. The emphasis will be on accuracy of mass determination, not just more masses of mediocre quality, to observationally detect the influence of age and metallicity on stellar evolution. Low-mass, unseen companions will be sought in wider binary systems. Known extrasolar planetary systems will be inspected to ensure that face-on binaries are not contaminating the sample even at a low level. Broader impact beyond the scientific and intellectual goals exists in three areas. First, CHARA is actively training the next generation of scientific and technical experts in the field of interferometry. A significant fraction of GSU astronomy graduate students are pursuing their PhD research with the Array. CHARA staff have participated in all of the NASA/JPL Michelson Summer Schools. Second, CHARA will enhance science awareness in the large and diverse undergraduate community at GSU by incorporating Array imagery (real-time in some cases) in undergraduate astronomy courses, which enroll approximately 700 students per semester. Several undergraduates will be recruited to participate in remote observations and data processing. Third, a CHARA Exhibit Hall on Mt. Wilson dramatically displays the historic 20-ft Michelson Stellar Interferometer, used at the 100-inch telescope in the 1920s. Thousands of visitors to the observatory grounds each year will have a unique opportunity to interactively learn how interferometry can probe stars to reveal their surfaces and fundamental properties. ***

乔治亚州立大学的高角分辨率天文学中心（CHARA）在加州威尔逊山上运行一个干涉测量阵列。CHARA阵列由6个1米口径的望远镜组成，以Y形排列，提供15条基线，长度从33米到331米不等。该阵列在可见光和近红外光谱区域工作，K和V波段的极限分辨率分别为1.6和0.4毫弧秒。就其望远镜的数量和孔径大小以及基线的长度而言，CHARA阵列是世界上同类设备中最强大的。CHARA阵列由佐治亚州立大学（GSU）、美国国家科学基金会（NSF）、W.M.凯克基金会以及大卫和露西尔·帕卡德基金会提供资金建造，准备承担对恒星天体物理学有广泛影响的广泛观测项目。该合同将主要通过在阵列站点维持足够的科学、技术和操作人员来支持这些项目。CHARA核心团队还开展了一系列合作，以更充分地利用该阵列的科学能力。由于其非常高的角度分辨率和良好的灵敏度和紫外线平面覆盖范围，CHARA阵列将有前所未有的机会获得所有温度的主序星以及演化恒星的恒星直径测量。精确的低能见度测量将描述恒星大气边缘变暗的特征。年轻恒星物体的大小和形状将被绘制出来。造父变星的脉动和它们的边缘变暗将被测量，以直接校准宇宙距离阶梯上的这一重要梯级。连续体和分子波段观测将描述演化恒星大气的尺度高度。Be恒星周围的圆盘和明亮的蓝色变星、沃尔夫-拉叶星和相互作用的双星的大量流出物将被探测和表征。在双星研究领域，该阵列将消除各种发现双星和测量其轨道运动的技术之间的非重叠选择效应的经典问题。它将解析大多数可接近的双星光谱，为广泛分布在HR图中的恒星提供质量、光度和半径的测量。重点将放在质量测定的准确性上，而不仅仅是更多质量一般的质量，以便在观测上探测年龄和金属丰度对恒星演化的影响。低质量、看不见的伴星将在更大的双星系统中寻找。已知的太阳系外行星系统将被检查，以确保正面的双星即使在低水平也不会污染样品。除了科学和知识目标之外，更广泛的影响存在于三个领域。首先，CHARA正在积极培养干涉测量领域的下一代科技专家。相当一部分的GSU天文学研究生正在阵列攻读他们的博士研究。CHARA的工作人员参加了所有的NASA/JPL迈克尔逊暑期学校。其次，CHARA将通过将阵列图像（在某些情况下是实时的）纳入每学期招收约700名学生的本科天文学课程，提高GSU庞大而多样化的本科生群体的科学意识。将招募几名本科生参与远程观测和数据处理。第三，威尔逊山上的CHARA展览厅戏剧性地展示了具有历史意义的20英尺迈克尔逊恒星干涉仪，该干涉仪在20世纪20年代用于100英寸望远镜。每年成千上万的游客将有一个独特的机会来互动地学习干涉测量法如何探测恒星，以揭示它们的表面和基本特性。＊＊＊