ASTRO-F
Encyclopedia
Akari is an infrared astronomy
satellite
developed by Japan Aerospace Exploration Agency
, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006 at 21:28 UTC
(06:28, 22 February JST
) by M-V rocket into Earth sun-synchronous orbit
. After its launch it was named Akari (あかり), which means light in Japanese
.
Its primary mission was to survey the entire sky in near-, mid- and far-infrared, through its 68.5 cm (27 in) aperture telescope.
coolant.
Its telescope mirror is made of silicon carbide
to save weight. The budget for the satellite was ¥
13,4 billion (~).
By early November 2006, first (phase-1) all-sky survey finished. Second (phase-2) all-sky survey started on 10 November 2006.
Due to the malfunction of sun-sensor after the launch, ejection of telescope aperture
lid was delayed, resulting the coolant lifespan estimate to be shortened to about 500 days from launch. However after JAXA estimated the remaining helium during early March 2007 observation time will be extended at least until 9 September.
On 11 July 2007, JAXA informed that 90 percent of the sky was scanned twice. Also around 3,500 selected targets have been observed so far.
On 26 August 2007, liquid-Helium coolant depleted, which means the completion of far- and mid-infrared observation. 94 percent of the sky was scanned and more than 5,000 pointed observations were done.
British and Japanese project team members were awarded a Daiwa Adrian Prize
in 2004 by The Daiwa Anglo-Japanese Foundation
in recognition of their collaboration.
During December 2007, JAXA performed orbit correction manoeuvres to bring Akari back into its ideal orbit. This was necessary because the boiled off helium
led to an increase in altitude. If this would have continued energy supply would have been cut off.
In May 2011, Akari suffered a major electrical failure that rendered its science instruments inoperable when the satellite is in the Earth's shadow. The operation of satellite was terminated officially on November 24, 2011.
The Akari All-Sky Survey Point Source Catalogues was released on March 30, 2010. http://darts.isas.jaxa.jp/astro/akari/ http://www.ir.isas.jaxa.jp/ASTRO-F/Observation/PSC/Public/
Astronomy and Astrophysics
, Vol. 514 (May 2010) was a feature issue of Akari's result.
Infrared astronomy
Infrared 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...
satellite
Space observatory
A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects...
developed by Japan Aerospace Exploration Agency
Japan Aerospace Exploration Agency
The , or JAXA, is Japan's national aerospace agency. Through the merger of three previously independent organizations, JAXA was formed on October 1, 2003, as an Independent Administrative Institution administered by the Ministry of Education, Culture, Sports, Science and Technology and the...
, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006 at 21:28 UTC
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
(06:28, 22 February JST
Japan Standard Time
Japan Standard Time or JST is the standard timezone of Japan, and is 9 hours ahead of UTC. For example, when it is midnight in UTC, it is 09:00 in Japan Standard Time. There is no daylight saving time, though its introduction has been debated several times. Japan Standard Time is the same as...
) by M-V rocket into Earth sun-synchronous orbit
Sun-synchronous orbit
A Sun-synchronous orbit is a geocentric orbit which combines altitude and inclination in such a way that an object on that orbit ascends or descends over any given point of the Earth's surface at the same local mean solar time. The surface illumination angle will be nearly the same every time...
. After its launch it was named Akari (あかり), which means light in Japanese
Japanese language
is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...
.
Its primary mission was to survey the entire sky in near-, mid- and far-infrared, through its 68.5 cm (27 in) aperture telescope.
Technical design
Its designed lifespan, of far- and mid-infrared sensors, is 550 days, limited by its liquid heliumHelium
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...
coolant.
Its telescope mirror is made of silicon carbide
Silicon carbide
Silicon carbide , also known as carborundum, is a compound of silicon and carbon with chemical formula SiC. It occurs in nature as the extremely rare mineral moissanite. Silicon carbide powder has been mass-produced since 1893 for use as an abrasive...
to save weight. The budget for the satellite was ¥
Japanese yen
The is the official currency of Japan. It is the third most traded currency in the foreign exchange market after the United States dollar and the euro. It is also widely used as a reserve currency after the U.S. dollar, the euro and the pound sterling...
13,4 billion (~).
History
By mid-August 2006, Akari finished around 50 percent of the all sky survey.By early November 2006, first (phase-1) all-sky survey finished. Second (phase-2) all-sky survey started on 10 November 2006.
Due to the malfunction of sun-sensor after the launch, ejection of telescope aperture
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...
lid was delayed, resulting the coolant lifespan estimate to be shortened to about 500 days from launch. However after JAXA estimated the remaining helium during early March 2007 observation time will be extended at least until 9 September.
On 11 July 2007, JAXA informed that 90 percent of the sky was scanned twice. Also around 3,500 selected targets have been observed so far.
On 26 August 2007, liquid-Helium coolant depleted, which means the completion of far- and mid-infrared observation. 94 percent of the sky was scanned and more than 5,000 pointed observations were done.
British and Japanese project team members were awarded a Daiwa Adrian Prize
Daiwa Adrian Prize
This Daiwa Adrian Prize is an award given by The Daiwa Anglo-Japanese Foundation to scientists who have made significant achievements in science through Anglo-Japanese collaborative research....
in 2004 by The Daiwa Anglo-Japanese Foundation
The Daiwa Anglo-Japanese Foundation
The Daiwa Anglo-Japanese Foundation is a United Kingdom-based charity established in 1988 to support closer links between Britain and Japan...
in recognition of their collaboration.
During December 2007, JAXA performed orbit correction manoeuvres to bring Akari back into its ideal orbit. This was necessary because the boiled off 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...
led to an increase in altitude. If this would have continued energy supply would have been cut off.
In May 2011, Akari suffered a major electrical failure that rendered its science instruments inoperable when the satellite is in the Earth's shadow. The operation of satellite was terminated officially on November 24, 2011.
Results
- Star formation over three generations in the nebulaNebulaA nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...
IC4954/4955 in the constellation VulpeculaVulpeculaVulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle .-Stars:There are no stars brighter than 4th magnitude in...
. - The first infrared detection of a supernova remnant in the Small Magellanic CloudSmall Magellanic CloudThe Small Magellanic Cloud is a dwarf galaxy. It has a diameter of about 7,000 light-years and contains several hundred million stars. It has a total mass of approximately 7 billion times the mass of our Sun....
- Detection of mass-loss from relatively young red-giant stars in the globular clusterGlobular clusterA globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
NGC 104 - Detection of the molecular gas surrounding the active galactic nucleusActive galactic nucleusAn active galactic nucleus is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum. Such excess emission has been observed in the radio, infrared, optical, ultra-violet, X-ray and...
in the ultra luminous infrared galaxyLuminous infrared galaxyA luminous infrared galaxy , is a galactic body whose defining characteristic is in emitting more than 1011 solar luminosities in the far-infrared part of the electromagnetic spectrum. A more luminous system, emitting more than 1012 solar luminosities in the far-infrared, is called ultraluminous... - The constellation Orion and the winter Milky WayMilky WayThe 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...
at 140 micrometreMicrometreA micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm... - Star forming region in the constellation CygnusCygnus (constellation)Cygnus is a northern constellation lying on the plane of the Milky Way. Its name is the Latinized Hellenic word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross...
- Active star formation viewed from the outside: The peculiar spiral galaxy M101Pinwheel GalaxyThe Pinwheel Galaxy is a face-on spiral galaxy distanced 21 million light-years away in the constellation Ursa Major, first discovered by Pierre Méchain on March 27, 1781, and communicated to Charles Messier who verified its position for inclusion in the Messier Catalogue as one of its final...
- Dust processing in the supernovaSupernovaA supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
remnants in the Large Magellanic CloudLarge Magellanic CloudThe Large Magellanic Cloud is a nearby irregular galaxy, and is a satellite of the Milky Way. At a distance of slightly less than 50 kiloparsecs , the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal and Canis Major Dwarf Galaxy lying closer to the center...
The Akari All-Sky Survey Point Source Catalogues was released on March 30, 2010. http://darts.isas.jaxa.jp/astro/akari/ http://www.ir.isas.jaxa.jp/ASTRO-F/Observation/PSC/Public/
Astronomy and Astrophysics
Astronomy and Astrophysics
* Astronomy and Astrophysics has a 2010 impact factor of 4.410.-See also:*The Astronomy and Astrophysics Review*Advanced Satellite for Cosmology and Astrophysics*Astronomy & Geophysics*Astronomical Journal*Astrophysical Journal...
, Vol. 514 (May 2010) was a feature issue of Akari's result.