ELODIE was an

echelle An echelle grating (from French ''échelle'', meaning "ladder") is a type of diffraction grating characterised by a relatively low groove density, but a groove shape which is optimized for use at high incidence angles and therefore in high diffract ...

spectrograph installed on the 1.93m reflector at the

Observatoire de Haute-Provence The Haute-Provence Observatory (OHP, french: Observatoire de Haute-Provence) is an astronomical observatory in the southeast of France, about 90 km east of Avignon and 100 km north of Marseille. It was established in 1937 as a national ...

in south-eastern

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

. Its optical instrumentation was developed by André Baranne from the

Marseille Observatory Marseille Observatory (french: Observatoire de Marseille) is an astronomical observatory located in Marseille, France, with a history that goes back to the early 18th century. In its 1877 incarnation, it was the discovery site of a group of gal ...

. The purpose of the instrument was

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

detection by the

radial velocity method Doppler spectroscopy (also known as the radial-velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in t ...

. ELODIE's first light was achieved in 1993. The instrument was decommissioned in August 2006 and replaced in September 2006 by SOPHIE, a new instrument of the same type but with improved features.

Characteristics

The instrument could observe the

electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...

over a

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...

range of 389.5 nm to 681.5 nm in a single exposure, split into 67

spectral orders ''Spectral'' is a 2016 3D military science fiction, supernatural horror fantasy and action-adventure thriller war film directed by Nic Mathieu. Written by himself, Ian Fried, and George Nolfi from a story by Fried and Mathieu. The film stars ...

. The instrument, which was located in a temperature-controlled room, was fed with

optical fibers An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means ...

from the

Cassegrain focus The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas, the main characteristic being that the optical path folds back onto itself, relative to the ...

. The observatory provided an integrated data reduction pipeline which fully reduced the spectra immediately after acquisition and allowed the user to measure

radial velocities The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection o ...

to an accuracy as good as ±7 m/s. Over 34,000 spectra were taken with ELODIE, over 20,000 of which are publicly available through a dedicated on-line archive. The instrument was the result of a collaboration between the observatories of Haute-Provence,

Geneva Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevra ; rm, Genevra is the List of cities in Switzerland, second-most populous city in Switzerland (after Zürich) and the most populous city of Romandy, the French-speaki ...

and

Marseille Marseille ( , , ; also spelled in English as Marseilles; oc, Marselha ) is the prefecture of the French department of Bouches-du-Rhône and capital of the Provence-Alpes-Côte d'Azur region. Situated in the camargue region of southern Franc ...

. A publication describing the instrument appeared in '' Astronomy & Astrophysics Supplements''.

Discovered planets

The first

to be discovered orbiting a Sun-like star, 51 Pegasi b, was discovered in 1995 using ELODIE.

Michel Mayor Michel Gustave Édouard Mayor (; born 12 January 1942) is a Swiss astrophysicist and professor emeritus at the University of Geneva's Department of Astronomy. He formally retired in 2007, but remains active as a researcher at the Observatory o ...

and

Didier Queloz Didier Patrick Queloz (; born 23 February 1966) is a Swiss astronomer. He is the Jacksonian Professor of Natural Philosophy at the University of Cambridge, where he is also a fellow of Trinity College, Cambridge, as well as a professor at the ...

received the

Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...

in 2019 for their achievement. Over twenty such planets have been found with ELODIE. The instrument was also used to find a planet by the

transit method Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty o ...

References

External links

*
The ELODIE Archive
{{Exoplanet search projects Spectrographs Astronomical instruments Telescope instruments Exoplanet search projects

Characteristics

Discovered planets

See also

References

External links