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14 July 2010 Along the path towards extremely precise radial velocity measurements
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In the last six years, thanks to the very high radial velocity precision of the HARPS spectrograph, it was possible to detect 21 out of the 30 super-Earth (extrasolar planets masses below 20 times the mass of the Earth) discovered up to date. The radial velocity precision of the instrument is estimated around 80 cm/s on a single measurement. The main instrumental limitations are the wavelength calibration and the stability of the light injection. We address both factors and present the results of recent tests on the HARPS spectrograph. We have identified the laser frequency comb as the ideal wavelength calibrator, due to the width, density and flux of the lines, and to its intrinsic stability. The results from the recent tests that we performed on HARPS are encouraging. The accurate guiding of the telescope is critical to maintain a stable light distribution at the injection stage, where the light is sent into the spectrograph entrance fiber. To pursue this goal we are testing a secondary guiding system which is able to apply the guiding corrections twenty times faster than the primary guiding system.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gaspare Lo Curto, Christophe Lovis, Tobias Wilken, Gerardo Avila, Bruno Chazelas, Massimiliano Esposito, Theodor W. Hänsch, Jonay Gonzáez-Hernández, Ronald Holzwarth, Gerardo Ihle, Antonio Manescau, Luca Pasquini, Francesco Pepe, Rafael Rebolo, Alex Segovia, Peter Sinclaire, Tilo Steinmetz, Thomas Udem, and François Wildi "Along the path towards extremely precise radial velocity measurements", Proc. SPIE 7735, Ground-based and Airborne Instrumentation for Astronomy III, 77350Z (14 July 2010);


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