IRAS
Encyclopedia
The Infrared Astronomical Satellite (IRAS) was the first-ever space-based observatory
to perform a survey of the entire sky
at infrared
wavelength
s.
Launched on January 25, 1983, its mission lasted ten months. The telescope was a joint project of the United States
(NASA
), the Netherlands
(NIVR
), and the United Kingdom
(SERC
). Over 250,000 infrared sources were observed at 12, 25, 60, and 100 micrometer wavelengths.
, still enduring their star
-formation stage. Many other sources are normal stars with disks of dust around them, possibly the early stage of a planetary system
formation. New discoveries included a dust disk around Vega
and the first images of the Milky Way Galaxy's
core.
IRAS's life, like that of most of infrared satellites that followed after, was limited by its cooling system. To effectively work in the infrared domain, the telescope must be cooled to cryogenic temperatures. In IRAS's case, 73 kilograms of superfluid
helium
kept the telescope at a temperature of 2 kelvin
s (about -271 °C), keeping the satellite cool by evaporation
. The on-board supply of liquid helium was depleted after 10 months on November 22, 1983, causing the telescope temperature to rise, preventing further observations. The spacecraft continues to orbit close to the earth.
IRAS was designed to catalogue fixed sources, so it scanned the same region of sky several times. Jack Meadows led a team at Leicester University, including John Davies and Simon Green, which searched the rejected sources for moving objects. This led to the discovery of three asteroid
s, including 3200 Phaethon
(an Apollo asteroid
and the parent body of the Geminid
meteor shower
), six comets, and a huge dust trail associated with comet Tempel-2. The comet
s included 126P/IRAS, 161P/Hartley-IRAS
, and comet IRAS-Araki-Alcock
(C/1983 H1), which made a close approach to the Earth in 1983. Out of the six comets IRAS found, four were long period and two were short period comets.
and possibly so close to Earth
that it would be part of this solar system
." However, further analysis revealed that, of several unidentified objects, nine were distant galaxies and the tenth was "intergalactic cirrus
". None were found to be Solar System bodies.
On December 10, 1983, Washington Post summarized an interview with JPL
that an unidentified body possibly as large as the giant planet Jupiter and possibly so close to Earth it would be part of this solar system has been found in the direction of the constellation Orion by an orbiting telescope aboard the U.S. infrared astronomical satellite. Though it turned out to be a young distant galaxy.
s have continued and greatly expanded the study of the infrared Universe, such as the Infrared Space Observatory
launched in 1995, the Spitzer Space Telescope
launched in 2003, and the AKARI
Space Telescope launched in 2006.
A next generation of infrared space telescopes began when NASA's Wide-field Infrared Survey Explorer
launched December 14, 2009 aboard a Delta II rocket from Vandenberg Air Force Base in California. Known as WISE, the telescope provided results hundreds of times more sensitive than IRAS at the shorter wavelengths, and also had an extended mission into 2011 even after its coolant supply ran out.
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...
to perform a survey of the entire sky
Sky
The sky is the part of the atmosphere or outer space visible from the surface of any astronomical object. It is difficult to define precisely for several reasons. During daylight, the sky of Earth has the appearance of a pale blue surface because the air scatters the sunlight. The sky is sometimes...
at infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
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...
s.
Launched on January 25, 1983, its mission lasted ten months. The telescope was a joint project of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
(NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
), the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
(NIVR
Netherlands Agency for Aerospace Programmes
The Netherlands Agency for Aerospace Programmes was the official space-exploration agency of the Dutch government until 2009....
), and the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
(SERC
Science and Engineering Research Council
The Science and Engineering Research Council used to be the UK agency in charge of publicly funded scientific and engineering research activities including astronomy, biotechnology and biological sciences, space research and particle physics...
). Over 250,000 infrared sources were observed at 12, 25, 60, and 100 micrometer wavelengths.
Mission
IRAS was the first observatory to perform an all-sky survey at infrared wavelengths. It mapped 96% of the sky four times, at 12, 25, 60 and 100 micrometres wavelengths, with resolutions ranging from 30 arcseconds at wavelength 12 micrometers to 2 arcminutes at wavelength 100 micrometers. It discovered about 350,000 sources, many of which are still awaiting identification. About 75,000 of those are believed to be starburst galaxiesStarburst galaxy
A starburst galaxy is a galaxy in the process of an exceptionally high rate of star formation, compared to the usual star formation rate seen in most galaxies. Galaxies are often observed to have a burst of star formation after a collision or close encounter between two galaxies...
, still enduring their star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
-formation stage. Many other sources are normal stars with disks of dust around them, possibly the early stage of a planetary system
Planetary system
A planetary system consists of the various non-stellar objects orbiting a star such as planets, dwarf planets , asteroids, meteoroids, comets, and cosmic dust...
formation. New discoveries included a dust disk around Vega
Vega
Vega is the brightest star in the constellation Lyra, the fifth brightest star in the night sky and the second brightest star in the northern celestial hemisphere, after Arcturus...
and the first images of the Milky Way Galaxy's
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
core.
IRAS's life, like that of most of infrared satellites that followed after, was limited by its cooling system. To effectively work in the infrared domain, the telescope must be cooled to cryogenic temperatures. In IRAS's case, 73 kilograms of superfluid
Superfluid
Superfluidity is a state of matter in which the matter behaves like a fluid without viscosity and with extremely high thermal conductivity. The substance, which appears to be a normal liquid, will flow without friction past any surface, which allows it to continue to circulate over obstructions and...
helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
kept the telescope at a temperature of 2 kelvin
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
s (about -271 °C), keeping the satellite cool by evaporation
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
. The on-board supply of liquid helium was depleted after 10 months on November 22, 1983, causing the telescope temperature to rise, preventing further observations. The spacecraft continues to orbit close to the earth.
IRAS was designed to catalogue fixed sources, so it scanned the same region of sky several times. Jack Meadows led a team at Leicester University, including John Davies and Simon Green, which searched the rejected sources for moving objects. This led to the discovery of three asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s, including 3200 Phaethon
3200 Phaethon
3200 Phaethon is an asteroid with an unusual orbit that brings it closer to the Sun than any other named asteroid . For this reason, it was named after the Greek myth of Phaëton, son of the sun god Helios...
(an Apollo asteroid
Apollo asteroid
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, the first asteroid of this group to be discovered by Karl Wilhelm Reinmuth...
and the parent body of the Geminid
Geminids
The Geminids are a meteor shower caused by the object 3200 Phaethon, which is thought to be a Palladian asteroid. This would make the Geminids, together with the Quadrantids, the only major meteor showers not originating from a comet...
meteor shower
Meteor shower
A meteor shower is a celestial event in which a number of meteors are observed to radiate from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller...
), six comets, and a huge dust trail associated with comet Tempel-2. The comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s included 126P/IRAS, 161P/Hartley-IRAS
161P/Hartley-IRAS
-External links:*...
, and comet IRAS-Araki-Alcock
Comet IRAS-Araki-Alcock
Comet IRAS–Araki–Alcock is a small comet that, in 1983, made the closest approach to the earth of any comet in 200 years; only Lexell's Comet, in 1770, and 55P/Tempel-Tuttle, in 1366, are thought to have come closer.The comet was named after its discoverers – the Infrared Astronomical Satellite and...
(C/1983 H1), which made a close approach to the Earth in 1983. Out of the six comets IRAS found, four were long period and two were short period comets.
News event
The observatory also made headlines briefly with the discovery of an "unknown object" at first described as "possibly as large as the giant planet JupiterJupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
and possibly so close to Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
that it would be part of this solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
." However, further analysis revealed that, of several unidentified objects, nine were distant galaxies and the tenth was "intergalactic cirrus
Infrared Cirrus
Infrared cirrus are filamentary structures seen in infrared light. The name is given because the structure looks cloud-like in appearance. First detected by the Infrared Astronomy Satellite at wavelengths of 60 and 100 micrometres.-External links:...
". None were found to be Solar System bodies.
On December 10, 1983, Washington Post summarized an interview with JPL
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...
that an unidentified body possibly as large as the giant planet Jupiter and possibly so close to Earth it would be part of this solar system has been found in the direction of the constellation Orion by an orbiting telescope aboard the U.S. infrared astronomical satellite. Though it turned out to be a young distant galaxy.
Later surveys
Several space infrared telescopeInfrared telescope
An infrared telescope is a telescope that uses infrared light to detect celestial bodies.Infrared light is one of several types of radiation present in the electromagnetic spectrum....
s have continued and greatly expanded the study of the infrared Universe, such as the Infrared Space Observatory
Infrared Space Observatory
The Infrared Space Observatory was a space telescope for infrared light designed and operated by the European Space Agency , in cooperation with ISAS and NASA...
launched in 1995, the Spitzer Space Telescope
Spitzer Space Telescope
The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...
launched in 2003, and the AKARI
Akari
Akari is a Japanese surname and given name and term meaning "light" or "glimmer". It is also associated with:* AKARI, in astronomy, is an infrared astronomy satellite developed by JAXA, in cooperation with institutes of Europe and Korea...
Space Telescope launched in 2006.
A next generation of infrared space telescopes began when NASA's Wide-field Infrared Survey Explorer
Wide-field Infrared Survey Explorer
Wide-field Infrared Survey Explorer is a NASA infrared-wavelength astronomical space telescope launched on December 14, 2009, and decommissioned/hibernated on February 17, 2011 when its transmitter was turned off...
launched December 14, 2009 aboard a Delta II rocket from Vandenberg Air Force Base in California. Known as WISE, the telescope provided results hundreds of times more sensitive than IRAS at the shorter wavelengths, and also had an extended mission into 2011 even after its coolant supply ran out.
| 3200 Phaethon 3200 Phaethon 3200 Phaethon is an asteroid with an unusual orbit that brings it closer to the Sun than any other named asteroid . For this reason, it was named after the Greek myth of Phaëton, son of the sun god Helios... |
October 11, 1983 |
| 3728 IRAS 3728 IRAS 3728 IRAS is a main belt asteroid discovered in 1983. It is about 6.07 miles in diameter according to data from the infrared survey by the IRAS satellite 1983. It is one of the three asteroids discovered with data from Infrared Astronomical Satellite in 1983, and was named in honour of the... |
August 23, 1983 |
| (10714) 1983 QG | August 31, 1983 |
See also
- Diffuse Infrared Background ExperimentDiffuse Infrared Background ExperimentDiffuse Infrared Background Experiment was an experiment on NASA's COBE mission, to survey the diffuse infrared sky. The DIRBE instrument was an absolute radiometer with an off-axis folded-Gregorian reflecting telescope, with 19 cm diameter aperture...
, a infrared sky survey on COBECOBEThe COsmic Background Explorer , also referred to as Explorer 66, was a satellite dedicated to cosmology. Its goals were to investigate the cosmic microwave background radiation of the universe and provide measurements that would help shape our understanding of the cosmos.This work provided...
(1989) - Infrared astronomyInfrared astronomyInfrared astronomy is the branch of astronomy and astrophysics that studies astronomical objects visible in infrared radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers...