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SOPHIE+: First results of an octagonal-section fiber for high-precision radial velocity measurements

F. Bouchy, R. F. Díaz, G. Hébrard, L. Arnold, I. Boisse, X. Delfosse, S. Perruchot, A. Santerne

High-precision spectrographs play a key role in exoplanet searches and Doppler asteroseismology using the radial velocity technique. The 1 ms-1 level of precision requires very high stability and uniformity of the illumination of the spectrograph. In fiber-fed spectrographs such as SOPHIE, the fiber-link scrambling properties are one of the main conditions for high precision. To significantly improve the radial velocity precision of the SOPHIE spectrograph, which was limited to 5–6 ms-1, we implemented a piece of octagonal-section fiber in the fiber link. We present here the scientific validation of the upgrade of this instrument, demonstrating a real improvement. The upgraded instrument, renamed SOPHIE+, reaches radial velocity precision in the range of 1–2 ms-1. It is now fully efficient for the detection of low-mass exoplanets down to 5–10 M and for the identification of acoustic modes down to a few tens of cm s-1.

instrumentation: spectrographs – techniques: radial velocities – planetary systems – stars: oscillations

Astronomy & Astrophysics
Volume 549, Number of pages A49_1
2013 January

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia