Fomalhaut With Disk Ring And Extrasolar Planet B
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Fomalhaut is the brightest star in the southern constellation of
Piscis Austrinus Piscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish", in contrast with the larger constellation Pisces, which represents a pair of fish. Before the 20th century, it was also known a ...
, the "Southern Fish", and one of the brightest stars in the night sky. It has the Bayer designation Alpha Piscis Austrini, which is Latinized from α Piscis Austrini, and is abbreviated Alpha PsA or α PsA. This is a class A star on the main sequence approximately from the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
as measured by the Hipparcos astrometry satellite. Since 1943, the
spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...
of this star has served as one of the stable anchor points by which other stars are classified. It is classified as a
Vega Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, a ...
-like star that emits excess infrared radiation, indicating it is surrounded by a
circumstellar disk A circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the ...
. Fomalhaut,
K-type main-sequence star A K-type main-sequence star, also referred to as a K-type dwarf or an orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence star ...
TW Piscis Austrini TW Piscis Austrini (also Fomalhaut B) is a dwarf star in the constellation Piscis Austrinus. It lies relatively close to the Sun, at an estimated distance of 24.8 light-years. To an observer on Earth the star is visually separated fro ...
, and M-type, red dwarf star LP 876-10 constitute a
triple system In algebra, a triple system (or ternar) is a vector space ''V'' over a field F together with a F-trilinear map : (\cdot,\cdot,\cdot) \colon V\times V \times V\to V. The most important examples are Lie triple systems and Jordan triple systems. The ...
, even though the companions are separated by approximately 8 degrees. Fomalhaut was the first stellar system with an extrasolar planet candidate (designated Fomalhaut b, later named Dagon) imaged at visible wavelengths. Analysis of existing and new data suggests Fomalhaut b is not a planet, rather an expanding dust disk resulting from a former collision. The image was published in ''
Science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...
'' in November 2008. Fomalhaut is the third-brightest star (as viewed from Earth) known to have a planetary system, after the Sun and Pollux.


Nomenclature

''α Piscis Austrini'' ( Latinised to ''Alpha Piscis Austrini'') is the system's Bayer designation. It also bears the
Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England. They are named for John Flamsteed who first used them while co ...
of ''24 Piscis Austrini''. The classical astronomer
Ptolemy Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importance ...
put it in
Aquarius Aquarius may refer to: Astrology * Aquarius (astrology), an astrological sign * Age of Aquarius, a time period in the cycle of astrological ages Astronomy * Aquarius (constellation) * Aquarius in Chinese astronomy Arts and entertainme ...
, as well as Piscis Austrinus. In the 17th centrury, Johann Bayer firmly planted it in the primary position of Piscis Austrinus. Following Ptolemy,
John Flamsteed John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called '' Atlas C ...
in 1725 additionally denoted it ''79 Aquarii''. The current designation reflects modern consensus on Bayer's decision, that the star belongs in Piscis Austrinus. Under the rules for naming objects in multiple star systems, the three components – Fomalhaut, TW Piscis Austrini and LP 876-10 – are designated A, B and C, respectively. On its discovery, the planet was designated Fomalhaut b. The star's traditional name derives from ''Fom al-Haut'' from scientific Arabic ' "the mouth of the outhernFish" (literally, "mouth of the whale"), a translation of how Ptolemy labeled it. In 2016, the
International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
organized a
Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...
(WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included the name Fomalhaut for this star. In July 2014, the
International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
(IAU) launched
NameExoWorlds NameExoWorlds (also known as IAU NameExoWorlds) is the name of various projects managed by the International Astronomical Union (I.A.U.) to encourage names to be submitted for astronomical objects, which would later be considered for official ad ...
, a process for giving proper names to certain exoplanets. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Dagon for Fomalhaut b. The winning name was proposed by Todd Vaccaro and forwarded by th
St. Cloud State University Planetarium
of St. Cloud, Minnesota,
United States of America The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...
, to the IAU for consideration.
Dagon Dagon ( he, דָּגוֹן, ''Dāgōn'') or Dagan ( sux, 2= dda-gan, ; phn, 𐤃𐤂𐤍, Dāgān) was a god worshipped in ancient Syria across the middle of the Euphrates, with primary temples located in Tuttul and Terqa, though many attes ...
was a
Semitic deity Ancient Semitic religion encompasses the polytheistic religions of the Semitic peoples from the ancient Near East and Northeast Africa. Since the term ''Semitic'' itself represents a rough category when referring to cultures, as opposed to lan ...
, often represented as half-man, half-fish.


Fomalhaut A

At a declination of −29.6°, Fomalhaut is located south of the
celestial equator The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. This plane of reference bases the equatorial coordinate system. In other words, the celestial equator is an abstract proj ...
, and hence is best viewed from the Southern Hemisphere. However, its southerly declination is not as great as that of stars such as
Acrux Acrux is the brightest star in the southern constellation of Crux. It has the Bayer designation α Crucis, which is Latinised to Alpha Crucis and abbreviated Alpha Cru or α Cru. With a combined visual magnitude of +0.76, it is the 1 ...
, Alpha Centauri and
Canopus Canopus is the brightest star in the southern constellation of Carina and the second-brightest star in the night sky. It is also designated α Carinae, which is Latinised to Alpha Carinae. With a visual apparent magnitude ...
, meaning that, unlike them, Fomalhaut is visible from a large part of the Northern Hemisphere as well, being best seen in autumn. Its declination is greater than that of
Sirius Sirius is the brightest star in the night sky. Its name is derived from the Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated Alpha CM ...
and similar to that of
Antares Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by σ Scorpii and τ ...
. At 40°N, Fomalhaut rises above the horizon for eight hours and reaches only 20° above the horizon, while
Capella Capella is the brightest star in the northern constellation of Auriga. It has the Bayer designation α Aurigae, which is Latinised to Alpha Aurigae and abbreviated Alpha Aur or α Aur. Capella is the sixth-brightest star in ...
, which rises at approximately the same time, will stay above the horizon for twenty hours. Fomalhaut can be located in northern latitudes by the fact that the western (right-hand) side of the
Square of Pegasus Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and is one of the 88 constellations recognised today. W ...
points to it. Continuing the line from Beta to Alpha Pegasi towards the southern horizon, Fomalhaut is about 45˚ south of Alpha Pegasi, with no bright stars in between.


Properties

Fomalhaut is a young star, for many years thought to be only 100 to 300 million years old, with a potential lifespan of a billion years. A 2012 study gave a slightly higher age of . The surface temperature of the star is around . Fomalhaut's mass is about 1.92 times that of the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
, its luminosity is about 16.6 times greater, and its diameter is roughly 1.84 times as large. Fomalhaut is slightly metal-deficient compared to the Sun, which means it is composed of a smaller percentage of elements other than hydrogen and helium. The metallicity is typically determined by measuring the abundance of iron in the photosphere relative to the abundance of hydrogen. A 1997
spectroscopic Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...
study measured a value equal to 93% of the Sun's abundance of iron. A second 1997 study deduced a value of 78%, by assuming Fomalhaut has the same metallicity as the neighboring star
TW Piscis Austrini TW Piscis Austrini (also Fomalhaut B) is a dwarf star in the constellation Piscis Austrinus. It lies relatively close to the Sun, at an estimated distance of 24.8 light-years. To an observer on Earth the star is visually separated fro ...
, which has since been argued to be a physical companion. In 2004, a stellar evolutionary model of Fomalhaut yielded a metallicity of 79%. Finally, in 2008, a spectroscopic measurement gave a significantly lower value of 46%. Fomalhaut has been claimed to be one of approximately 16 stars belonging to the
Castor Moving Group The Castor Moving Group, or Castor stream, is a moving group of stars sharing similar velocities and directions. The stars that have been identified as part of the group include Castor, Fomalhaut, Vega, α Cephei and α Librae. While the rep ...
. This is an association of stars which share a common motion through space, and have been claimed to be physically associated. Other members of this group include Castor and
Vega Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, a ...
. The
moving group In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space. Stellar kinematics encompasses the measurement of stellar velocities in the Milky Way and its satellites as well a ...
has an estimated age of and originated from the same location. More recent work has found that purported members of the Castor Moving Group appear to not only have a wide range of ages, but their velocities are too different to have been possibly associated with one another in the distant past. Hence, "membership" to this dynamical group has no bearing on the age of the Fomalhaut system.


Debris disks and suspected planet

Fomalhaut is surrounded by several
debris disk A debris disk (American English), or debris disc (Commonwealth English), is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris di ...
s. The inner disk is a high-carbon small-grain (10–300 nm) ash disk, clustering at 0.1 AU from the star. Next is a disk of larger particles, with inner edge 0.4-1 AU of the star. The innermost disk is unexplained as yet. The outermost disk is at a radial distance of , in a toroidal shape with a very sharp inner edge, all inclined 24 degrees from edge-on. The dust is distributed in a belt about 25 AU wide. The geometric center of the disk is offset by about from Fomalhaut. The disk is sometimes referred to as "Fomalhaut's Kuiper belt". Fomalhaut's dusty disk is believed to be protoplanetary, and emits considerable
infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
radiation. Measurements of Fomalhaut's rotation indicate that the disk is located in the star's equatorial plane, as expected from theories of star and planet formation. On November 13, 2008, astronomers announced an object, which they assumed to be an
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 ...
, orbiting just inside the outer debris ring. This was the first extrasolar orbiting object to be seen with visible light, captured by the
Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...
. A planet's existence had been previously suspected from the sharp, elliptical inner edge of that disk. The mass of the planet, Fomalhaut b, was estimated to be less than three times the mass of
Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...
, and at least the mass of Neptune. (at 3 minutes 45 seconds: "... has to be less than three Jupiter masses. In fact our lower limit to Fomalhaut b is Neptune") There are indications that the orbit is not apsidally aligned with the dust disk, which may indicate that additional planets may be responsible for the dust disk's structure. However, M-band images taken from the
MMT Observatory The MMT Observatory (MMTO) is an astronomical observatory on the site of Fred Lawrence Whipple Observatory (IAU observatory code 696). The Whipple observatory complex is located on Mount Hopkins, Arizona, US (55 km south of Tucson) in the S ...
put strong limits on the existence of gas giants within 40 AU of the star, and Spitzer Space Telescope imaging suggested that the object Fomalhaut b was more likely to be a dust cloud. In 2012, two independent studies confirmed that Fomalhaut b does exist, but it is shrouded by debris, so it may be a gravitationally-bound accumulation of rubble rather than a whole planet. Herschel Space Observatory images of Fomalhaut reveal that a large amount of fluffy micrometer-sized dust is present in the outer dust belt. Because such dust is expected to be blown out of the system by stellar radiation pressure on short timescales, its presence indicates a constant replenishment by collisions of planetesimals. The fluffy morphology of the grains suggests a cometary origin. The collision rate is estimated to be approximately 2000 kilometre-sized comets per day. Observations of the star's outer dust ring by the
Atacama Large Millimeter Array The Atacama Large Millimeter/submillimeter Array (ALMA) is an astronomical interferometer of 66 radio telescopes in the Atacama Desert of northern Chile, which observe electromagnetic radiation at millimeter and submillimeter wavelengths. The ...
point to the existence of two planets in the system, neither one at the orbital radius proposed for the HST-discovered Fomalhaut b. If there are additional planets from 4 to 10 AU, they must be under 20 MJ; if from 2.5 outward, then 30 MJ. , - , Outer hot disk , colspan="4", 0.21–0.62 AU ''or'' 0.88–1.08 AU , — , —


Fomalhaut B (TW Piscis Austrini)

Fomalhaut forms a binary star with the K4-type star
TW Piscis Austrini TW Piscis Austrini (also Fomalhaut B) is a dwarf star in the constellation Piscis Austrinus. It lies relatively close to the Sun, at an estimated distance of 24.8 light-years. To an observer on Earth the star is visually separated fro ...
(TW PsA), which lies away from Fomalhaut, and its space velocity agrees with that of Fomalhaut within , consistent with being a bound companion. A recent age estimate for TW PsA () agrees very well with the isochronal age for Fomalhaut (), further arguing for the two stars forming a physical binary. The designation TW Piscis Austrini is astronomical nomenclature for a
variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as e ...
. Fomalhaut B is a
flare star A flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to the magnetic energy stored in th ...
of the type known as a
BY Draconis variable BY Draconis variables are variable stars of late spectral types, usually K or M, and typically belong to the main sequence. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in thei ...
. It varies slightly in
apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...
, ranging from 6.44 to 6.49 over a 10.3 day period. While smaller than the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
, it is relatively large for a flare star. Most flare stars are red M-type dwarfs. In 2019, a team of researchers analyzing the astrometry, radial velocity measurements, and images of Fomalhaut B suggested the existence of a planet orbiting the star with a mass of Jupiter masses, and a poorly defined orbital period with an estimate loosely centering around 25 years.


Fomalhaut C (LP 876-10)

LP 876-10 is also associated with the Fomalhaut system, making it a trinary star. In October 2013, Eric Mamajek and collaborators from the RECONS consortium announced that the previously known high-proper-motion star LP 876-10 had a distance, velocity, and color-magnitude position consistent with being another member of the Fomalhaut system. LP 876-10 was originally catalogued as a high-proper-motion star by Willem Luyten in his 1979 NLTT catalogue; however, a precise trigonometric parallax and radial velocity was only measured quite recently. LP 876-10 is a red dwarf of spectral type M4V, and located even farther from Fomalhaut A than TW PsA—about 5.7° away from Fomalhaut A in the sky, in the neighbouring constellation
Aquarius Aquarius may refer to: Astrology * Aquarius (astrology), an astrological sign * Age of Aquarius, a time period in the cycle of astrological ages Astronomy * Aquarius (constellation) * Aquarius in Chinese astronomy Arts and entertainme ...
, whereas both Fomalhaut A and TW PsA are located in constellation
Piscis Austrinus Piscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish", in contrast with the larger constellation Pisces, which represents a pair of fish. Before the 20th century, it was also known a ...
. Its current separation from Fomalhaut A is about , and it is currently located away from TW PsA (Fomalhaut B). LP 876-10 is located well within the tidal radius of the Fomalhaut system, which is . Although LP 876-10 is itself catalogued as a binary star in the
Washington Double Star Catalog The Washington Double Star Catalog, or WDS, is a catalog of double stars, maintained at the United States Naval Observatory. The catalog contains positions, magnitudes, proper motions and spectral types and has entries for (as of June 2017) 141, ...
(called "WSI 138"), there was no sign of a close-in stellar companion in the imaging, spectral, or astrometric data in the Mamajek et al. study. In December 2013, Kennedy et al. reported the discovery of a cold dusty debris disk associated with Fomalhaut C, using infrared images from the Herschel Space Observatory. Multiple-star systems hosting multiple debris disks are exceedingly rare.


Etymology and cultural significance

Fomalhaut has had various names ascribed to it through time, and has been recognized by many cultures of the northern hemisphere, including the
Arab The Arabs (singular: Arab; singular ar, عَرَبِيٌّ, DIN 31635: , , plural ar, عَرَب, DIN 31635: , Arabic pronunciation: ), also known as the Arab people, are an ethnic group mainly inhabiting the Arab world in Western Asia, ...
s,
Persians The Persians are an Iranian ethnic group who comprise over half of the population of Iran. They share a common cultural system and are native speakers of the Persian language as well as of the languages that are closely related to Persian. ...
, and
Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...
. It marked the solstice in 2500 BC. It was also a marker for the worship of Demeter in Eleusis. * It was called ''Hastorang'' by the
Persia Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
ns, one of the four "
royal stars In astrology, the royal stars of Persia are Aldebaran, Regulus, Antares and Fomalhaut. They were regarded as the guardians of the sky during the time of the Persian Empire (550 BC–330 BC) in the area of modern-day Iran. The Persians believed tha ...
".Richard Hinckley Allen: Star Names — Their Lore and Meaning ("Piscis Australis, the Southern Fish", pp. 344–47)
/ref> * The Latin names are ' "the mouth of the Southern Fish". * A folk name among the early Arabs was ''Difdi‘ al Awwal'' ( ') "the first frog" (the second frog is
Beta Ceti Beta Ceti (β Ceti, abbreviated Beta Cet, β Cet), officially named Diphda , is the brightest star in the constellation of Cetus. Although designated 'beta', it is actually brighter than the 'alpha' star in the constellation ( Alpha Ceti ...
). * The
Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are ofte ...
北落師門/北落师门 (
Mandarin Mandarin or The Mandarin may refer to: Language * Mandarin Chinese, branch of Chinese originally spoken in northern parts of the country ** Standard Chinese or Modern Standard Mandarin, the official language of China ** Taiwanese Mandarin, Stand ...
: Běiluòshīmén), meaning ''North Gate of the Military Camp'', because this star is marking itself and stands alone in ''North Gate of the Military Camp'' asterism,
Encampment Camp may refer to: Outdoor accommodation and recreation * Campsite or campground, a recreational outdoor sleeping and eating site * a temporary settlement for nomads * Camp, a term used in New England, Northern Ontario and New Brunswick to descri ...
mansion (see:
Chinese constellation Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" ( Chinese ''xīng guān''). The Chinese asterisms are generally smaller than the constellations of Hellenisti ...
). 北落师门 (Běiluòshīmén), westernized into ''Pi Lo Sze Mun'' in R.H. Allen's work. * To the Moporr Aboriginal people of South Australia, it is a masculine being called ''Buunjill''. The
Wardaman people The Wardaman people are a small group of Aboriginal Australians living about South-West of Katherine, on Menngen Aboriginal Land Trust in the Northern Territory of Australia. Language Wardaman is a non Pama-Nyungan language. Though close to ...
of the Northern Territory called Fomalhaut ''Menggen'' —white cockatoo. Fomalhaut/Earthwork B, in Mounds State Park near Anderson, Indiana, lines up with the rising of the star Fomalhaut in the fall months, according to the Indiana Department of Natural Resources. In 1980, astronomer Jack Robinson proposed that the rising azimuth of Fomalhaut was marked by cairn placements at both the
Bighorn The bighorn sheep (''Ovis canadensis'') is a species of sheep native to North America. It is named for its large horns. A pair of horns might weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates three distinct subspec ...
and Moose Mountain
Medicine Wheel To some indigenous peoples of North America, the medicine wheel is a metaphor for a variety of spiritual concepts. A medicine wheel may also be a stone monument that illustrates this metaphor. Historically, most medicine wheels follow the basic ...
s in Wyoming, USA and Saskatchewan, Canada, respectively. The ''New Scientist'' magazine termed it the "Great
Eye of Sauron Sauron (pronounced ) is the title character and the primary antagonist, through the forging of the One Ring, of J. R. R. Tolkien's ''The Lord of the Rings'', where he rules the land of Mordor and has the ambition of ruling the whole of Midd ...
", due to its shape and debris ring, when viewed from a distance, bearing similarity to the aforementioned "Eye" in the Peter Jackson ''
Lord of the Rings ''The Lord of the Rings'' is an epic high-fantasy novel by English author and scholar J. R. R. Tolkien. Set in Middle-earth, intended to be Earth at some time in the distant past, the story began as a sequel to Tolkien's 1937 children's boo ...
'' films. USS ''Fomalhaut'' (AK-22) was a
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
navy
amphibious cargo ship Amphibious cargo ships were U.S. Navy ships designed specifically to carry troops, heavy equipment and supplies in support of amphibious assaults, and to provide naval gunfire support during those assaults. A total of 108 of these ships were built ...
.


See also

*
2M1207 2M1207, 2M1207A or 2MASSW J12073346–3932539 is a brown dwarf located in the constellation Centaurus; a companion object, 2M1207b, may be the first exoplanet, extrasolar planetary-mass object, planetary-mass companion to be directly image ...
*
GJ 758 Gliese 758 is a star in the northern constellation of Lyra. At about magnitude 6 it is a challenge to view with the naked eye even in good seeing conditions, but can be easily seen through a small telescope or binoculars. Parallax ...
*
HR 8799 HR 8799 is a roughly 30 million-year-old main-sequence star located away from Earth in the constellation of Pegasus. It has roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also ...
* Direct imaging of extrasolar planets *
List of extrasolar planets These are lists of exoplanets. Most of these were discovered by the Kepler space telescope. There are an additional 2,054 potential exoplanets from Kepler's first mission yet to be confirmed, as well as 978 from its " Second Light" mission and ...
* List of star systems within 25–30 light-years


Notes


References


External links

*
Preprint of planet discovery paper

Astrobites summary of Janson et al. 2012, the Spitzer IR non-detection of Fomalhaut b

Astrobites summary of Boley et al. 2012, the ALMA observations of the Fomalhaut ring system



Researchers find that bright nearby double star Fomalhaut is actually a triple
(Astronomy magazine : October 8, 2013) {{DEFAULTSORT:Fomalhaut A-type main-sequence stars Triple star systems 3 M-type main-sequence stars K-type main-sequence stars BY Draconis variables Hypothetical planetary systems Circumstellar disks Castor Moving Group Piscis Austrinus Piscis Austrini, Alpha 8728 Durchmusterung objects Piscis Austrini, 24 0879 81 216956 113368
Fomalhaut Fomalhaut is the brightest star in the southern constellation of Piscis Austrinus, the "Southern Fish", and one of the brightest stars in the night sky. It has the Bayer designation Alpha Piscis Austrini, which is Latinized from ...
Arabic words and phrases