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

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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.