SOPHIE échelle spectrograph

SOPHIE ( French acronym for Spectrographe pour l' Observation of Phénomènes of Intérieurs stellaires et des Exoplanètes ) is a high resolution échelle spectrograph installed on the 1.93 m telescope of the Observatoire de Haute -Provence in southeastern France. Application is on the one hand asteroseismology on the other hand, the discovery of extrasolar planets by the radial velocity method. It is an evolution and replacement of älterten ELODIE spectrograph. The instrument was made ​​available in October 2006, the astronomical community.

Properties

The electromagnetic spectrum is fed in the wavelength range of 387.2 nm to 694.3 nm, of the analysis. The spectrograph is thereby supplied by two different sets of fibers from the focus of the Cassegrainian telescope with light and driven in two different resolutions U and HR. The instrument is fully automated and has a built-in data reduction, which allows for each read cycle of the CCD sensor current, extremely accurate measurement of the radial velocity of the investigated objects.

HR mode

The HR mode is the higher resolution mode. Using a 40 micron exit slit can be reached with it a very high resolution of.

HE mode

The HE mode is the more efficient mode. This is used to a higher throughput at fainter objects to reach. The resolution capability is then limited.

G2 Echelle grating has 52.65 lines per millimeter, and thus a lattice constant of g = 19 microns. It was produced by the company Richardson Gratings. It has a blaze angle of at a total size of 20.4 cm × 40.8 cm.

Assembled it is in a fixed configuration. The spectrum is projected onto 44-82 E2V CCDs of 4096 × 2048 pixels, which are maintained at a constant temperature of 173 K. This diffraction grating to reach 41 orders of diffraction, where 39 of them are actually used.

Efficiency

A signal -to-noise ratio of V was for 90 minutes at an object with mV = 14.5 may be achieved in HE mode.

Stability over several months is the measurement of the radial velocity in the HR mode at 3-4 m / s For shorter periods accuracy of 1.3 m / s can be achieved.

More

Haute-Provence Observatory Cassegrain reflector High Accuracy Radial velocity Planet Searcher Astronomy and Astrophysics arXiv Digital Object Identifier
738871
de