Fiber-laser Astro-comb as a Robust Wavelength Calibrator for Astrophysical Spectrographs

第一批围绕其他恒星运行的行星是在最近几十年才被发现的，从那时起，科学家们就对这类系外行星的普遍程度以及它们的一些特征的惊人性质感到惊讶。寻找更多的系外行星和收集更好的统计数据以充分了解它们（以及我们生活的行星系统）是现代研究的一个充满活力的领域。一个特别紧迫的科学方向是确定一颗系外行星是类地行星，这需要测量行星的半径和质量。当行星从恒星前面经过时，可以通过卫星观测来测量半径；质量是通过极其精确地监测中心恒星的径向速度来测量的，因为它的运动受到行星引力的影响，与它的质量成比例。该项目将开发基于强大的、现场兼容的新型激光技术的频率校准器，该技术应将径向速度精度降至10厘米/秒以下（相比之下，地球引起的太阳反冲速度约为9厘米/秒）。这些系统正朝着由标准天文台人员长期、连续操作的方向发展，不需要现场的专业激光专家，也不需要经常进行调整。激光梳发展项目将培养数名在超快光学和天文仪器建造与观测物理方面的研究生和本科生。这里开发的许多技术将在其他科学学科中得到富有成效的应用，例如分子光谱学。该项目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资金。

The first planets around other stars were discovered only within the last few decades, and since then scientists have been surprised by how common such exoplanets are, and by the surprising nature of some of their characteristics. The search for more exoplanets and the drive to gather better statistics to fully understand them (and so the planetary system in which we live) is a vigorous area of modern research. A particularly urgent scientific direction is establishing that an exoplanet is earthlike, which requires measurement of both the radius and the mass of the planet. Radius can be measured by satellite observations when the planet passes in front of the star; mass is measured by extremely precise monitoring of the radial velocity of the central star, since its motions are influenced by the gravitational tug of the planet in proportion to its mass.This project will develop frequency calibrators based on robust, field-compatible new laser technologies that should push radial velocity precision down to below 10 cm/s (for comparison, the recoil velocity of the Sun caused by the earth is about 9 cm/s). These systems are moving toward long-term, continuous operation by standard observatory personnel, without specialized laser experts on-site or any need to make frequent adjustments.The laser-comb development project will train several graduate and undergraduate students in the physics of ultrafast optics and astronomical instrument building and observation. Many of the techniques developed here will find fruitful application in other scientific disciplines, such as molecular spectroscopy.Funding for this project is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.