Skip to Main content Skip to Navigation
Conference papers

Higher-precision radial velocity measurements with the SOPHIE spectrograph using octagonal-section fibers

Abstract : High-precision spectrographs play a key role in exoplanet searches using the radial velocity technique. But at the accuracy level of 1 m.s-1, required for super-Earth characterization, stability of fiber-fed spectrograph performance is crucial considering variable observing conditions such as seeing, guiding and centering errors and, telescope vignetting. In fiber-fed spectrographs such as HARPS or SOPHIE, the fiber link scrambling properties are one of the main issues. Both the stability of the fiber near-field uniformity at the spectrograph entrance and of the far-field illumination on the echelle grating (pupil) are critical for high-precision radial velocity measurements due to the spectrograph geometrical field and aperture aberrations. We conducted tests on the SOPHIE spectrograph at the 1.93-m OHP telescope to measure the instrument sensitivity to the fiber link light feeding conditions: star decentering, telescope vignetting by the dome,and defocussing. To significantly improve on current precision, we designed a fiber link modification considering the spectrograph operational constraints. We have developed a new link which includes a piece of octagonal-section fiber, having good scrambling properties, lying inside the former circular-section fiber, and we tested the concept on a bench to characterize near-field and far-field scrambling properties. This modification has been implemented in spring 2011 on the SOPHIE spectrograph fibers and tested for the first time directly on the sky to demonstrate the gain compared to the previous fiber link. Scientific validation for exoplanet search and characterization has been conducted by observing standard stars.
Complete list of metadata

Cited literature [15 references]  Display  Hide  Download

http://hal.in2p3.fr/in2p3-00626103
Contributor : Danielle Cristofol <>
Submitted on : Friday, September 23, 2011 - 2:43:35 PM
Last modification on : Monday, March 29, 2021 - 3:22:25 PM
Long-term archiving on: : Tuesday, November 13, 2012 - 2:25:27 PM

File

Arnaud_ProcSPIE_8151-40.pdf
Files produced by the author(s)

Identifiers

Citation

S. Perruchot, F. Bouchy, B. Chazelas, R. F. Díaz, G. Hébrard, et al.. Higher-precision radial velocity measurements with the SOPHIE spectrograph using octagonal-section fibers. SPIE Optics + Photonics 2011 Event News and Photo, Aug 2011, San Diego Californie, United States. ⟨10.1117/12.892466⟩. ⟨in2p3-00626103⟩

Share

Metrics

Record views

1320

Files downloads

932