ELODIE spectrograph
Encyclopedia
ELODIE was an echelle
type spectrograph
installed at the Observatoire de Haute-Provence 1.93m reflector in south-eastern France
for the Northern Extrasolar Planet Search. Its optical instrumentation was developed by André Baranne from the Marseille Observatory
. The purpose of this instrument was extrasolar planet
detection by the radial velocity method. This instrument was also used for the M-Dwarf Programmes.
ELODIE first light was achieved in 1993. ELODIE was decommissioned in August 2006 and replaced in September 2006 by SOPHIE
, a new instrument of the same type but with improved features.
wavelength
range is 389.5 nm to 681.5 nm in a single exposure, split into 67 spectral orders. The instrument, which was located in a temperature-controlled room, was fed with optical fibers from the Cassegrain focus. One of the unique features of ELODIE was an integrated data reduction pipeline which fully reduces the spectra
immediately after acquisition and allows the user to measure highly accurate radial velocities
through cross-correlation with a numerical mask. This accuracy can reach ±7 m/s.
Over 34,000 spectra have been taken with this instrument so far, over 20,000 of which are publicly available through a dedicated on-line archive. ELODIE was the result of a collaboration between the observatories of Haute-Provence, Geneva
and Marseille. A publication describing the instrument appeared in Astronomy & Astrophysics Supplements.
to be discovered orbiting a Sun-like star, 51 Pegasi b
, was discovered in 1995 using this instrument. Over twenty such planets have been found with ELODIE. This instrument was also used to find a planet by the transit method.
Echelle grating
An echelle grating is a type of diffraction grating which is characterised by a relatively low groove density but is optimized for high diffraction orders. Echelle gratings are, like other types of diffraction grating, used in spectrometers and similar instruments, such as HARPS, and numerous...
type spectrograph
Spectrograph
A spectrograph is an instrument that separates an incoming wave into a frequency spectrum. There are several kinds of machines referred to as spectrographs, depending on the precise nature of the waves...
installed at the Observatoire de Haute-Provence 1.93m reflector in south-eastern France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
for the Northern Extrasolar Planet Search. Its optical instrumentation was developed by André Baranne from the Marseille Observatory
Marseille Observatory
Marseille Observatory or Observatoire de Marseille is an astronomical observatory run by the University of Provence. It is located near Marseille, France. In its first incarnation, it was the discovery site of a group of galaxies known as Stephan's Quintet or Hickson 92, discovered by Édouard...
. The purpose of this instrument was extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
detection by the radial velocity method. This instrument was also used for the M-Dwarf Programmes.
ELODIE first light was achieved in 1993. ELODIE was decommissioned in August 2006 and replaced in September 2006 by SOPHIE
SOPHIE échelle spectrograph
The SOPHIE échelle spectrograph is a high-resolution echelle spectrograph installed on the 1.93m reflector telescope at the Haute-Provence Observatory located in south-eastern France...
, a new instrument of the same type but with improved features.
Characteristics
The electromagnetic spectrumElectromagnetic spectrum
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object....
wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
range is 389.5 nm to 681.5 nm in a single exposure, split into 67 spectral orders. The instrument, which was located in a temperature-controlled room, was fed with optical fibers from the Cassegrain focus. One of the unique features of ELODIE was an integrated data reduction pipeline which fully reduces the spectra
Spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
immediately after acquisition and allows the user to measure highly accurate radial velocities
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...
through cross-correlation with a numerical mask. This accuracy can reach ±7 m/s.
Over 34,000 spectra have been taken with this instrument so far, over 20,000 of which are publicly available through a dedicated on-line archive. ELODIE was the result of a collaboration between the observatories of Haute-Provence, Geneva
Observatory of Geneva
Observatoire de Genève is an astronomical observatory at Sauverny in the municipality of Versoix, Canton of Geneva, Switzerland...
and Marseille. A publication describing the instrument appeared in Astronomy & Astrophysics Supplements.
Planets discovered by ELODIE
The first extrasolar planetExtrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
to be discovered orbiting a Sun-like star, 51 Pegasi b
51 Pegasi b
51 Pegasi b , sometimes though unofficially named Bellerophon, is an extrasolar planet approximately 50 light-years away in the constellation of Pegasus...
, was discovered in 1995 using this instrument. Over twenty such planets have been found with ELODIE. This instrument was also used to find a planet by the transit method.
| Planet Planet A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,... |
Date announced |
|---|---|
| 51 Pegasi b 51 Pegasi b 51 Pegasi b , sometimes though unofficially named Bellerophon, is an extrasolar planet approximately 50 light-years away in the constellation of Pegasus... |
6 October 1995 |
| Gliese 876 b Gliese 876 b Gliese 876 b is an extrasolar planet orbiting the red dwarf star Gliese 876. It completes one orbit in approximately 61 days. Discovered in June 1998, Gliese 876 b was the first planet to be discovered orbiting a red dwarf star.- Discovery :... |
1998 |
| 14 Herculis b 14 Herculis b 14 Herculis b or 14 Her b is an extrasolar planet approximately 59 light-years away in the constellation of Hercules. The planet was found orbiting the star 14 Herculis, with a mass that would likely make the planet a Jovian planet roughly the same size as Jupiter but much more massive. It was... |
6 July 1998 |
| HD 209458 b HD 209458 b HD 209458 b is an extrasolar planet that orbits the Solar analog star HD 209458 in the constellation Pegasus, some 150 light-years from Earth's solar system, with evidence of water vapor.... |
1999 |
See also
- List of extrasolar planets
- CORALIE spectrographCORALIE spectrographThe CORALIE spectrograph is an echelle type spectrograph used for astronomy. This instrument used with a telescope to measure star spectra for the Doppler effect to detect the presence of extrasolar planets by the radial velocity method...
was a similar instrument used for the Survey for Southern Extra-solar Planets.