nfrared Astronomical Satellite (IRAS)

IRAS beside some of its all-sky images
General information
Organization	NASA / NIVR / SERC
Major contractors	Ball Aerospace / Fokker Space / Hollandse Signaal
Launch date	25 January 1983
Launched from	SLC-2 West,  Vandenberg AFB,  California
Launch vehicle	Delta 3910
Mission length	10 months
Mass	1083 kg
Type of orbit	sun-synchronous polar orbit
Orbit height	900 km
Orbit period	100 minutes
Location	in orbit, deactivated
Telescope style	Ritchey-Chrétien
Wavelength	Long-wavelength to farinfrared
Diameter	0.57 m
Collecting area	0.202 m2[1]
Focal length	5.5 m, f/9.6
Instruments
Main array	62 detectors
Low Resolution Spectrometer (LRS)	8 to 22 µm slitlessspectrometer
Chopped Photometric Channel (CPC)	low-quality mapping
Website	IRAS website

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 micrometre 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 galaxies, 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 superfluidhelium kept the telescope at a temperature of 2 kelvins (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 asteroids, 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 comets 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.[3]

The observatory also made headlines briefly with the discovery of an "unknown object" that was at first described as "possibly as large as the giant planet Jupiter and possibly so close to Earth that it would be part of this solar system."[4] However, further analysis revealed that, of several unidentified objects, nine were distant galaxies and the tenth was "intergalactic cirrus".[5] None were found to be Solar System bodies.[5]

Several space infrared telescopes have continued and greatly expanded the study of the infrared Universe, such as the Infrared Space Observatory launched in 1995, theSpitzer Space Telescope launched in 2003, and the AKARI Space Telescope launched in 2006.

The 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. Nicknamed WISE, the telescope is expected to provide results hundreds of times more sensitive than the IRAS.

On December 10, 1983 The 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 that 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 is suspected that the object was a young distant galaxy.[6][7]

See also

• Diffuse Infrared Background Experiment, a infrared sky survey on COBE (1989)
• WISE 2010
• WFIRST 2020 (planned)
• Infrared astronomy & Infrared telescope
• List of space telescopes

References

Comet IRAS-Araki-Awcock

From Wikipedia, de free encycwopedia

Comet IRAS-Araki-Awcock, viewed ininfrared wight by de Infrared Astronomicaw Satewwite.

Comet IRAS-Araki-Awcock (formaw designation C/1983 H1, formerwy 1983 VII) is a smaww comet dat, in 1983, made de cwosest approach to de earf (about 5,000,000 km) of any comet in 200 years; onwy Lexeww's Comet, in 1770, and55P/Tempew-Tuttwe, in 1366, are dought to have come cwoser.

The comet was named after its discoverers - de Infrared Astronomicaw Satewwite and two amateur astronomers, de highwy-respected George Awcock of de United Kingdom and Genichi Araki of Japan (bof men were schoowteachers by profession, awdough Awcock was retired). Awcock had made his discovery simpwy by observing drough de window of his home, usingbinocuwars.[1][2]

During de cwosest approach de comet appeared as a circuwar cwoud about de size of de fuww moon, having no discernibwe taiw, and shining at a naked eye magnitude of 3-4. It swept across de sky at an incredibwe speed of some 30 degrees per day.

It is a wong-period comet, wif an orbitaw period of around 964 years, and is de parent comet of de minor Eta Lyrid meteor shower.[3] This shower's radiant wies betweenVega and Cygnus and produces 1 or 2 meteors an hour in mid-May wif a peak between May 9 and May 11.

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