SOPHIE spectrograph

SOPHIE ( acronym for French S pectrographe pour l ' O bservation of Ph énomènes of I ntérieurs stellaires et des E xoplanètes ) is a high-resolution échelle - spectrograph installed on 1,93- m - mirror telescope of the Observatoire de Haute-Provence in southeastern France . The area of application is on the one hand asteroseismology and on the other hand the discovery of extrasolar planets using the radial velocity method . It is a further development and replacement of the older ELODIE spectrograph . The instrument was made available to the astronomical community in October 2006.

properties

The electromagnetic spectrum is submitted for analysis in the wavelength range from 387.2 nm to 694.3 nm. The spectrograph is fed with light through two different sets of glass fibers from the Cassegrain focus of the telescope and driven in two different resolutions HE and HR. The instrument is fully automated and has integrated data reduction , which allows extremely precise measurement of the radial speed of the examined objects with each read cycle of the CCD sensor .

HR mode

The HR mode is the higher-resolution operating mode. With a 40 μm exit aperture, you can achieve a very high resolution of . ${\ displaystyle R = {\ lambda \ over \ Delta \ lambda} = 75 {.} 000}$

HE mode

The HE mode is the more efficient operating mode. This is used to achieve a higher throughput for objects with less light. The resolution is then limited to here. ${\ displaystyle R = {\ lambda \ over \ Delta \ lambda} = 40000}$

The G2-Échelle diffraction grating has 52.65 lines per millimeter and therefore a grating constant of g = 19 μm. It was made by the Richardson Gratings company . It has a blaze angle of at a total size of 20.4 cm × 40.8 cm. ${\ displaystyle \ theta _ {B} = 65 ^ {\ circ}}$

It is mounted in a fixed configuration. The spectrum is at 44-82 E2V CCDs in of 4096 × 2048 pixels projected that at a constant temperature of 173 K are maintained. With this diffraction grating one reaches 41 diffraction orders, 39 of which are actually used.

Efficiency

A signal-to-noise ratio in V of was achieved for 90 minutes for an object with m _V = 14.5 mag in HE mode. ${\ displaystyle {\ frac {S} {N}} = 27}$

The stability over several months is 3–4 m / s when measuring the radial velocities in HR mode. Accuracies of 1.3 m / s can be achieved over shorter periods.

additional

Web links

SOPHIE website

Individual evidence

↑ Mosser et al. : Asteroseismology of Procyon with SOPHIE . In: Astronomy and Astrophysics . 478, No. 1, 2008, pp. 197-202. arxiv : 0712.1368 . bibcode : 2008A & A ... 478..197M . doi : 10.1051 / 0004-6361: 20078337 .
↑ ^a ^b ^c Perruchot et al. : The SOPHIE spectrograph: design and technical key-points for high throughput and high stability . In: Proceedings of SPIE . 7014, 2008, p. 70140J. doi : 10.1117 / 12.787379 .

[1] Mosser et al. : Asteroseismology of Procyon with SOPHIE . In: Astronomy and Astrophysics . 478, No. 1, 2008, pp. 197-202. arxiv : 0712.1368 . bibcode : 2008A & A ... 478..197M . doi : 10.1051 / 0004-6361: 20078337 .

[SOPHIE-2] Perruchot et al. : The SOPHIE spectrograph: design and technical key-points for high throughput and high stability . In: Proceedings of SPIE . 7014, 2008, p. 70140J. doi : 10.1117 / 12.787379 .