Collaborative Research: Infrared RV Planet Search with Externally Dispersed Interferometry II: Optimization

合作研究：红外RV行星搜索与外部色散干涉测量II：优化

• 批准号: 0905932
• 负责人: James Lloyd
• 金额: $ 24.43万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0905932&HistoricalAwards=false
• 关键词: Collaborative; Research; Infrared; RV; Planet

One of the most effective means employed by astronomers to search for planets around stars other than our sun is to try to detect the velocity shift of the star as the planet moves about the star in its orbit. This well proven technique employs an instrument called a spectrograph to measure the small shifts in wavelength of features in a star's spectrum. The shifts are due to the familiar Doppler effect and can be directly related to the changes in the star's velocity. But these velocity shifts are very small, and in order to measure them with great accuracy it is necessary to employ some scheme to calibrate the wavelength of the light in the spectrograph. One relatively new technique is to use interferometry, measuring the "interference" of two beams of light when they come together. At a particular wavelength, the two beams of light will cause fringes to appear which are spaced according to their wavelengths. By measuring the spacing of these fringes, wavelengths can be determined very accurately. Dr. Jerry Edelstein of the University of California-Berkeley and Dr. James Lloyd of Cornell University are applying this technique to a spectrograph that works not in visual light, but in the infrared. Infrared light is very useful in the study of cooler and smaller stars which are more numerous than hot stars. Finding planets around these stars will give us a much clearer picture than we currently have of how planets are actually formed and evolve. Since these stars are cooler than the massive hot stars that have been most frequently studied, their habitable zones, the region at the distance from the star where conditions may be suitable for life to begin, are much closer to the parent star. Most of the planets discovered so far have been "gas giants" like Jupiter and are located too far from their star for biology as we know it to exist. But with this new instrument, smaller earth-like planets may be detected in the habitable zone of cool stars. Funding for this work is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.

天文学家寻找太阳以外恒星周围行星的最有效方法之一是尝试检测当行星绕恒星轨道运动时恒星的速度变化。 这项经过充分验证的技术采用一种称为光谱仪的仪器来测量恒星光谱中特征波长的微小变化。 这些变化是由于熟悉的多普勒效应造成的，并且可能与恒星速度的变化直接相关。但这些速度变化非常小，为了高精度地测量它们，有必要采用某种方案来校准光谱仪中的光的波长。一种相对较新的技术是使用干涉测量法，测量两束光汇聚在一起时的“干涉”。在特定波长下，两束光将导致出现条纹，条纹的间隔根据其波长而定。通过测量这些条纹的间距，可以非常准确地确定波长。加州大学伯克利分校的杰里·埃德尔斯坦博士和康奈尔大学的詹姆斯·劳埃德博士正在将这项技术应用于光谱仪，该光谱仪不是在可见光下工作，而是在红外光下工作。红外光对于研究比热恒星数量更多的较冷和较小的恒星非常有用。寻找这些恒星周围的行星将使我们比目前更清楚地了解行星是如何形成和演化的。 由于这些恒星比最常研究的大质量热恒星温度低，因此它们的宜居带（距离恒星较远、条件可能适合生命开始的区域）距离母恒星要近得多。迄今为止发现的大多数行星都是像木星这样的“气态巨行星”，并且距离它们的恒星太远，不适合我们所知的生物存在。但借助这种新仪器，可以在冷恒星的宜居带中探测到较小的类地行星。这项工作的资金由美国国家科学基金会天文科学部通过其先进技术和仪器计划提供。