Editing Fomalhaut

{{Short description|Triple star system in the constellation Piscis Austrinus}}
{{use dmy dates |date=May 2023}}
{{Starbox begin
 | name=Fomalhaut
}}
{{Starbox image
 | image=[[File:Heic0821f.jpg|290px]]
 | caption=DSS image of Fomalhaut, field of view 2.7×2.9 degrees.|credit=NASA, ESA, and the Digitized Sky Survey 2. Acknowledgment: Davide De Martin (ESA/Hubble)
}}
{{Starbox observe
 | epoch=J2000
 | constell=[[Piscis Austrinus]]
 | pronounce={{IPAc-en|ˈ|f|oʊ|m|əl|.|h|ɔː|t}},<ref>{{OED|Fomalhaut}}</ref> {{IPAc-en|f|oʊ|m|əl|ˈ|h|ɔː|t}}
 | ra={{RA|22|57|39.0465}}<ref name=aaa474_2_653/>
 | dec={{DEC|−29|37|20.050}}<ref name=aaa474_2_653/>
 | appmag_v=1.16<ref name=ducati/>
}}
{{Starbox character
 | class=A4V<ref name="Gray2006"/>
 | b-v=0.09<ref name="clpl4"/>
 | u-b=0.08<ref name="clpl4" />
 | variable=None
}}
{{Starbox astrometry
 | prop_mo_ra=+328.95<ref name=aaa474_2_653/>
 | prop_mo_dec=−164.67<ref name=aaa474_2_653/>
 | parallax=129.81
 | p_error=0.47
 | parallax_footnote = <ref name=aaa474_2_653/>
 | absmag_v=1.72<ref name="age_mam"/>
}}
{{Starbox detail
 | mass={{val|1.92|0.02}}<ref name=age_mam/>
 | age_myr={{val|440|40}}<ref name=age_mam/>
 | metal_fe = −0.03<ref name=mnras286_3/> to −0.34<ref name=aaa490_1/>
 | radius={{val|1.842|0.019}}<ref name=age_mam/>
 | gravity=4.21<ref name=aaa426/>
 | rotational_velocity = 93<ref name=aaa426/>
 | luminosity={{val|16.63|0.48}}<ref name=age_mam/>
 | temperature=8,590<ref name=age_mam/>
}}
{{Starbox catalog
 | names      = {{odlist | name=Fomalhaut | B=α&nbsp;Piscis&nbsp;Austrini, α&nbsp;PsA, Alpha&nbsp;PsA | F=24&nbsp;Piscis&nbsp;Austrini | CPD=−30°685 | FK5=867 | GJ=881 | HD=216956 | HIP=113368 | HR=8728 | SAO=191524 }}<ref name="SIMBAD"/>
}}
{{Starbox reference
 | Simbad=**+MAM+1 | sn=AC
 | Simbad2=**+SHY+106 | sn2=AB
 | Simbad3=Fomalhaut | sn3=A (Fomalhaut)
 | Simbad4=HD+216803 | sn4=B (TW PsA)
 | Simbad5=LP+876-10 | sn5=C (LP 876-10)
 | Simbad6=*+alf+PsA+b | sn6=planet b
 | NSTED=Fomalhaut
 | ARICNS=01877 | an=A (Fomalhaut)
 | ARICNS2=01875 | an2=B (TW PsA)
 | EPE=Fomalhaut
}}
{{Starbox image
|image={{Location map many|100x100|AlternativeMap=Piscis_Austrinus_constellation_map.svg
|alt=Fomalhaut A, B are located in the constellation Piscis Austrinus; Fomalhaut C is located in the constellation Aquarius.
|caption=Location of Fomalhaut A, B, C|border=infobox|width=290
|mark=Red_circle.svg
|marksize=18
|label=A
|position=left
|lat=55
|long=15.9
|mark2=Red_circle.svg
|label2=B
|lat2=45.4
|long2=17.7
|label3=C
|lat3=82
|long3=22.9
}}|caption=
}}
{{Starbox end}}

'''Fomalhaut''' ({{IPAc-en|uk|ˈ|f|ɒ|m|ə|l|əʊ||t}}, {{IPAc-en|us|ˈ|f|oʊ|m|ə|l|h|ɔː|t}}<ref>{{Cite LPD|3}}</ref>) is the brightest star in the southern [[constellation]] of [[Piscis Austrinus]], the Southern Fish, and [[list of brightest stars|one of the brightest stars]] in the night sky. It has the [[Bayer designation]] '''Alpha&nbsp;Piscis Austrini''', which is an alternative form of '''α&nbsp;Piscis Austrini''', and is abbreviated '''Alpha&nbsp;PsA''' or '''α&nbsp;PsA'''. This is a [[stellar classification|class A]] [[star]] on the [[main sequence]] approximately {{convert|25|ly|pc|lk=on}} from the [[Sun]] as measured by the [[Hipparcos]] astrometry satellite.<ref name=GSM/> Since 1943, the [[stellar spectrum|spectrum]] of this star has served as one of the stable anchor points by which other stars are classified.<ref name=baas25_1319/>

It is classified as a [[Vega]]-like star that emits [[infrared excess|excess infrared radiation]],<ref name="NYT-20230508">{{cite news |last=Andrews |first=Robin George |title=Webb Telescope Finds a Star Cloaked in 3 Rings of Ruined Worlds - Astronomers have gained a new understanding of the chaos that wreathes the bright star Fomalhaut with the help of the powerful space observatory. |url=https://www.nytimes.com/2023/05/08/science/fomalhaut-star-webb-telescope.html |date=8 May 2023 |work=[[The New York Times]] |url-status=live |archive-url=https://archive.today/20230508155830/https://www.nytimes.com/2023/05/08/science/fomalhaut-star-webb-telescope.html |archive-date=8 May 2023 |access-date=8 May 2023 }}</ref><ref name="Gaspar2023"/> indicating it is surrounded by a [[Debris disk|circumstellar disk]].<ref name=vegalikedisc/> Fomalhaut, [[K-type main-sequence star]] [[TW Piscis Austrini]], and [[Stellar classification#Class M|M-type]], [[red dwarf]] star [[LP 876-10]] constitute a [[Star system#Triple star systems|triple system]], even though the companions are separated by approximately 8 degrees.<ref name=Mamajek2013/><ref name=skyandtelescope2014-10-01/>

Fomalhaut was the first stellar system with an extrasolar planet candidate imaged at visible wavelengths, designated [[Fomalhaut b]]. However, analyses in 2019 and 2023 of existing and new observations indicate that Fomalhaut&nbsp;b is not a planet, but rather an expanding region of debris from a massive planetesimal collision.<ref name="gaspar20newhst"/><ref>{{Cite web|url=https://www.nasa.gov/feature/goddard/2020/exoplanet-apparently-disappears-in-latest-hubble-observations|title=Exoplanet Apparently Disappears in Latest Hubble Observations|last=Andreoli|first=Claire|date=20 April 2020|website=NASA|access-date=21 April 2020}}</ref><ref name="Gaspar2023"/>

== Nomenclature ==
[[File:PiscisAustrinusCC.jpg|thumb|left|upright|Fomalhaut is the brightest star in the constellation of Piscis Austrinus (center).]]

''α&nbsp;Piscis Austrini'', or ''Alpha&nbsp;Piscis Austrini'', is the system's [[Bayer designation]]. It also bears the [[Flamsteed designation]] of ''24 Piscis Austrini''. The classical astronomer [[Ptolemy]] included it in the constellation of [[Aquarius (constellation)|Aquarius]], along with the rest of Piscis Austrinus. In the 17th century, [[Johann Bayer]] firmly planted it in the primary position of Piscis Austrinus. Following Ptolemy, [[John Flamsteed]] in 1725 additionally denoted it ''79 Aquarii''. The current designation reflects modern consensus on Bayer's decision, that the star belongs in Piscis Austrinus.<ref>{{cite journal | last= Wagman | first= M. | title= Flamsteed's Missing Stars | journal= Journal for the History of Astronomy| volume= 18 | issue= 3 | page= 212 |date= August 1987 | bibcode= 1987JHA....18..209W | doi= 10.1177/002182868701800305| s2cid= 118445625}}</ref> 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.<ref>{{cite web |last1= Hartkopf |first1= William I. |last2= Mason |first2= Brian D. |title= Addressing confusion in double star nomenclature: The Washington Multiplicity Catalog |url= http://ad.usno.navy.mil/wds/wmc/wmc_post191.html |work= U.S. Naval Observatory |access-date= 2016-01-19 |archive-url= https://web.archive.org/web/20110517130354/http://ad.usno.navy.mil/wds/wmc/wmc_post191.html |archive-date=2011-05-17 }}</ref>

The star's traditional name derives from ''Fom al-Haut'' from scientific Arabic {{lang|ar|فم الحوت}}  ''{{transliteration|ar|fam al-ḥūt (al-janūbī)}}'' "the mouth of the [Southern] Fish" (literally, "mouth of the whale"), a translation of how Ptolemy labeled it.<ref>{{cite web | url= http://www.souledout.org/cosmology/highlights/fomalhaut/fomalhaut.html|title= Fomalhaut}}</ref><ref name=rhallen/><ref>
{{cite book
 |last1                = Couper
 |first1               = Heather
 |author-link1         = Heather Couper
 |last2                = Henbest
 |first2               = Nigel
 |author-link2         = Nigel Henbest
 |date                 = 5 December 2011
 |orig-date            = 2007
 |title                = The Story of Astronomy: How the universe revealed its secrets
 |url                  = https://books.google.com/books?id=wFUgoNrX0LMC
 |publisher            = Hachette UK
 |page                 = 
 |isbn                 = 978-1-84403-726-1
 |access-date          = 25 May 2024
 |quote                = Ptolemy [...] generally described stars by their positions in the constellation patterns: but this could get quite cumbersome, such as 'the northernmost of two stars close together over the little shield in the stern.' [...] The jewel in the constellation of Piscis Austrinus [...] is dubbed by Ptolemy as 'the mouth of the southern fish.' In Arabic, this became fam al-hut al-janub – our star Fomalhaut.
}} 
</ref>
''Fam'' in Arabic means "mouth", ''al'' "the", and ''ḥūt'' "fish"<ref>
[https://en.wiktionary.org/wiki/%D9%81%D9%85_%D8%A7%D9%84%D8%AD%D9%88%D8%AA#Arabic فم الحوت]
</ref>
or "whale".<ref>
[https://en.wiktionary.org/wiki/%D8%AD%D9%88%D8%AA#Arabic حوت]
</ref>
In 2016, the [[International Astronomical Union]] organized a [[IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref name="WGSN">{{cite web | url= https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}}</ref> to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016<ref name="WGSN1">{{cite web | url= http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title= Bulletin of the IAU Working Group on Star Names, No. 1 |access-date= 28 July 2016}}</ref> 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]] (IAU) launched [[NameExoWorlds]], a process for giving proper names to certain exoplanets.<ref>[http://www.iau.org/news/pressreleases/detail/iau1404/ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars]. IAU.org. 9 July 2014</ref> The process involved public nomination and voting for the new names.<ref>{{Cite web |url= http://nameexoworlds.iau.org/process |title= NameExoWorlds The Process |access-date=2015-09-05 |archive-date=2015-08-15 |archive-url= https://web.archive.org/web/20150815025117/http://www.nameexoworlds.iau.org/process }}</ref> In December 2015, the IAU announced "Dagon" as the winning name for Fomalhaut b.<ref>[http://www.iau.org/news/pressreleases/detail/iau1514/ Final Results of NameExoWorlds Public Vote Released], International Astronomical Union, 15 December 2015.</ref> The winning name was proposed by Todd Vaccaro and forwarded by the [http://web.stcloudstate.edu/planetarium/ St. Cloud State University Planetarium] of [[St. Cloud, Minnesota]], [[United States|United States of America]], to the IAU for consideration.<ref>{{Cite web|url= http://www.sctimes.com/story/news/local/2015/12/25/scsu-planetarium-names-exoplanet/77875858/|title= SCSU planetarium names an exoplanet}}</ref> [[Dagon]] was a [[Ancient Canaanite religion|Semitic deity]], often represented as half-man, half-fish.<ref>{{Cite web |url= http://nameexoworlds.iau.org/names |title= NameExoWorlds The Approved Names |access-date=2016-09-09 |archive-date=2018-02-01 |archive-url= https://web.archive.org/web/20180201043609/http://nameexoworlds.iau.org/names }}
</ref>

==Fomalhaut A==
[[File:ALMA observes a ring around the bright star Fomalhaut.jpg|left|thumb|Dust ring around Fomalhaut from the [[Atacama Large Millimeter Array|Atacama Large Millimeter/submillimeter Array]] (ALMA)<ref>{{cite news|title=ALMA Reveals Workings of Nearby Planetary System|url=http://www.eso.org/public/images/eso1216a/|access-date=13 April 2012|newspaper=ESO Press Release}}</ref> ]]

At a [[declination]] of −29.6°, Fomalhaut is located south of the [[Celestial coordinate system|celestial equator]], and hence is best viewed from the [[Southern Hemisphere]]. However, its southerly declination is not as great as that of stars such as [[Acrux]], [[Alpha Centauri]] and [[Canopus]], 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]] and similar to that of [[Antares]]. At 40°N, Fomalhaut rises above the horizon for eight hours and reaches only 20° above the horizon, while [[Capella (star)|Capella]], 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]] points to it. Continuing the line from [[Beta Pegasi|Beta]] to [[Alpha Pegasi]] towards the southern horizon, Fomalhaut is about 45˚{{clarify|date=December 2023}} south of Alpha Pegasi, with no bright stars in between.<ref>{{cite web|url=http://www.astronomyhouston.org/newsletters/guidestar/shallow-sky-object-month-fomalhaut|title=Shallow Sky Object of the Month: Fomalhaut|date=August 2013|website=Houston Astronomical Society|access-date=2014-07-30}}</ref>

===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.<ref name="age"/><ref name="lifespan"/> A 2012 study gave a slightly higher age of {{val|440|40|u=million years}}.<ref name="age_mam"/> The surface temperature of the star is around {{convert|8590|K|C|lk=on}}. Fomalhaut's mass is about 1.92 times that of the [[Sun]], its [[luminosity]] is about 16.6 times greater, and its diameter is roughly 1.84 times as large.<ref name="age_mam"/>

Fomalhaut is slightly [[metallicity|metal-deficient]] compared to the Sun, which means it is composed of a smaller percentage of elements other than hydrogen and helium.<ref name="aaa426" /> The metallicity is typically determined by measuring the abundance of iron in the [[photosphere]] relative to the abundance of hydrogen. A 1997 [[spectroscopic]] study measured a value equal to 93% of the Sun's abundance of iron.<ref name=mnras286_3/><ref name=metal group=nb/> A second 1997 study deduced a value of 78%, by assuming Fomalhaut has the same metallicity as the neighboring star [[TW Piscis Austrini]], which has since been argued to be a physical companion.<ref name="age_mam"/><ref name=apj475/> In 2004, a stellar evolutionary model of Fomalhaut yielded a metallicity of 79%.<ref name=aaa426/> Finally, in 2008, a spectroscopic measurement gave a significantly lower value of 46%.<ref name=aaa490_1/>

Fomalhaut has been claimed to be one of approximately 16 stars belonging to the [[Castor Moving Group]]. 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 (star)|Castor]] and [[Vega]]. The [[moving group]] has an estimated age of {{val|200|100|u=million years}} and originated from the same location.<ref name="age"/> 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.<ref name=Mamajek2013/> Hence, "membership" in this dynamical group has no bearing on the age of the Fomalhaut system.<ref name=Mamajek2013/>

===Debris disks and suspected planets===
{{See also|Fomalhaut b}}
[[File:Fomalhaut Dusty Debris Disk (MIRI Compass Image).png|thumb|left|Image of the asteroid belt by the [[James Webb Space Telescope]]<ref>{{Cite web |last=Adkins |first=Jamie |date=2023-05-08 |title=Webb Looks for Fomalhaut's Asteroid Belt and Finds Much More |url=http://www.nasa.gov/feature/goddard/2023/webb-looks-for-fomalhaut-s-asteroid-belt-and-finds-much-more |access-date=2023-05-08 |website=NASA}}</ref> with annotations by NASA.]][[File:Fomalhaut annotated.jpg|thumb|left|This image shows the discovery features in the debris disk of Fomalhaut from the  [[James Webb Space Telescope]] (JWST) as well as overlays of [[Hubble Space Telescope]] (HST) data and the [[Atacama Large Millimeter/submillimeter Array]] (ALMA).]]
[[File:Fomalhaut B entire-Hubble Telescope.jpg|thumb|right|The [[Debris ring|debris disk]] around the [[star]]]]
[[File:NASA's Hubble Reveals Rogue Planetary Orbit For Fomalhaut B.jpg|thumb|right|[[Debris ring]] around Fomalhaut showing location of [[Fomalhaut b]]—imaged by [[Hubble Space Telescope]]'s coronagraph.<br />(January 8, 2013; North is up, East left) ([[NASA]]).]]
Fomalhaut is surrounded by several [[debris disk]]s.

The inner disk is a high-carbon small-grain (10–300&nbsp;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.<ref name=vegalikedisc>{{cite journal | journal=Astrophysical Journal | volume=763 | issue=2 | page=119 | title=An interferometric study of the Fomalhaut inner debris disk II. Keck Nuller mid-infrared observations |arxiv=1211.7143 |date=2012 |bibcode = 2013ApJ...763..119M |doi = 10.1088/0004-637X/763/2/119 | last1=Mennesson | first1=B. | last2=Absil | first2=O. | last3=Lebreton | first3=J. | last4=Augereau | first4=J.-C. | last5=Serabyn | first5=E. | last6=Colavita | first6=M. M. | last7=Millan-Gabet | first7=R. | last8=Liu | first8=W. | last9=Hinz | first9=P. | last10=Thébault | first10=P. | s2cid=102339596}}</ref>

The outermost disk is at a radial distance of {{convert|133|AU|km mi|lk=in|abbr=on}}, in a [[Toroid (geometry)|toroidal shape]] with a very sharp inner edge, all inclined 24 degrees from edge-on.<ref name=nature435_7045_1067/><ref name=nature392_6678_788/> The dust is distributed in a belt about 25 AU wide. The geometric center of the disk is offset by about {{convert|15|AU|km mi|abbr=on}} from Fomalhaut.<ref>{{cite web | title=Fomalhaut's Kuiper Belt | work=Sky & Telescope | url=http://www.skyandtelescope.com/news/3310401.html?page=1&c=y | access-date=October 16, 2007 | date=2005-06-22 | archive-date=2014-03-18 | archive-url=https://web.archive.org/web/20140318123718/http://www.skyandtelescope.com/news/3310401.html?page=1&c=y }}</ref> The disk is sometimes referred to as "Fomalhaut's [[Kuiper belt]]". Fomalhaut's dusty disk is believed to be [[Protoplanetary disc|protoplanetary]],<ref name="nasaprot">{{cite web| title=Hubble Directly Observes a Planet Orbiting Another Star | url=http://www.nasa.gov/mission_pages/hubble/science/fomalhaut.html | access-date=November 13, 2008}}</ref> and emits considerable [[infrared]] 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.<ref>{{Cite journal|title=The spin-orbit alignment of the Fomalhaut planetary system probed by optical long baseline interferometry|journal=Astronomy and Astrophysics|volume=498|issue=3|pages=L41–L44|author=Le Bouquin, Jean-Baptiste|date=2009|arxiv=0904.1688|display-authors=etal|doi=10.1051/0004-6361/200911854|bibcode = 2009A&A...498L..41L |s2cid=17766995}}</ref>

[[Herschel Space Observatory]] images of Fomalhaut, analysed in 2012, 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.<ref>{{cite journal|title=Herschel images of Fomalhaut. An extrasolar Kuiper belt at the height of its dynamical activity|author=B. Acke |display-authors=etal |arxiv=1204.5037|type=class: astro-ph|date=2012|journal=Astronomy & Astrophysics|volume=540 |pages=A125 |doi = 10.1051/0004-6361/201118581 |bibcode = 2012A&A...540A.125A |s2cid=10506379 }}</ref> Observations of this outer dust ring by the [[Atacama Large Millimeter Array]] also suggested the possible existence of two planets in the system.<ref>{{Cite journal|title=Constraining the Planetary System of Fomalhaut Using High-Resolution ALMA Observations|journal=The Astrophysical Journal|volume=750|issue=1|pages=L21|author=Boley, A.|arxiv=1204.0007|type=class: astro-ph|date=2012|display-authors=etal|doi=10.1088/2041-8205/750/1/L21|bibcode = 2012ApJ...750L..21B |s2cid=73622306}}</ref> If there are additional planets from 4 to 10 AU, they must be under {{Jupiter mass|20}}; if from 2.5 outward, then {{Jupiter mass|20}}.<ref>{{cite journal|title=Coronagraphic Observations of Fomalhaut at Solar System Scales|arxiv=1212.1459|type=class: astro-ph|date=2012|journal=Astrophysical Journal|volume=764|issue=1|page=7|bibcode = 2013ApJ...764....7K |doi = 10.1088/0004-637X/764/1/7 |last1=Kenworthy|first1=Matthew A.|last2=Meshkat|first2=Tiffany|last3=Quanz|first3=Sascha P.|last4=Girard|first4=Julien H.|last5=Meyer|first5=Michael R.|last6=Kasper|first6=Markus|s2cid=54214491}}</ref>

On November 13, 2008, astronomers announced an [[extrasolar planet]] candidate, orbiting just inside the outer debris ring. This was the first extrasolar orbiting object candidate to be directly imaged in visible light, captured by the [[Hubble Space Telescope]].<ref>{{cite web |url=http://www.berkeley.edu/news/media/releases/2008/11/13_exoplanet.shtml |title=Hubble snaps first optical photo of exoplanet  |publisher=Berkeley News |date=2008-11-13 | access-date=2017-10-03 }}</ref><ref name="Kalas2008"/> The mass of the tentative planet, [[Fomalhaut b]], was estimated to be less than three times the mass of [[Jupiter]], and at least the mass of [[Neptune]]. However, M-band images taken from the [[MMT Observatory]] put strong limits on the existence of gas giants within 40 AU of the star,<ref>{{Cite journal|title=MMT/AO 5 micron Imaging Constraints on the Existence of Giant Planets Orbiting Fomalhaut at ~13–40 AU|journal=The Astrophysical Journal|volume=697|issue=2|pages=1928–1933|author=Kenworthy, Matthew A.|arxiv=0811.2443|year=2009|display-authors=etal|doi=10.1088/0004-637X/697/2/1928|bibcode = 2009ApJ...697.1928K |s2cid=119234101}}</ref> and [[Spitzer Space Telescope]] imaging suggested that the object Fomalhaut b was more likely to be a dust cloud.<ref>{{Cite journal|title=Infrared Non-detection of Fomalhaut b—Implications for the Planet Interpretation|journal=The Astrophysical Journal|volume=747|issue=2|page=116|author=Markus, J.|arxiv=1201.4388|date=2012|display-authors=etal|doi=10.1088/0004-637X/747/2/116|bibcode = 2012ApJ...747..116J |s2cid=119256885}}</ref> A later 2019 synthesis of new and existing direct observations of the object confirmed that it is expanding, losing brightness, has not enough mass to detectably perturb the outer ring while crossing it, and is probably a dispersing cloud of debris from a massive planetesimal collision on a hyperbolic orbit destined to leave the Fomalhaut&nbsp;A system.<ref name="gaspar20newhst"/> Further 2022 observations with the [[James Webb Space Telescope]] in mid-infrared failed to resolve the object in the {{val|25.5|u=um}} [[Mid-Infrared Instrument#Filters|MIRI wideband filter]] wavelength range, reported by the same team to be consistent with the previous result.<ref name="Gaspar2023"/>

The same 2022 JWST imaging data discovered another apparent feature in the outer disk, dubbed the "Great Dust Cloud".<ref name="Gaspar2023"/> However, another team's analysis, which included other existing data, preferred its interpretation as a coincident background object, not part of the outer ring.<ref name="Kennedy2023"/> Another 2023 study detected 10 point sources around Fomalhaut; all but one of these are background objects, including the "Great Dust Cloud", but the nature of the last is unclear. It may be a background object, or a planetary companion to Fomalhaut.<ref name="Ygouf2023"/>

{{OrbitboxPlanet begin
|table_ref = <ref name="vegalikedisc" /><ref name="gaspar20newhst" /><ref name="Kalas2013">{{cite journal|title=STIS Coronagraphic Imaging of Fomalhaut: Main Belt Structure and the Orbit of Fomalhaut b|author1=Kalas, Paul |author2=Graham, James R. |author3=Fitzgerald, Michael P. |author4=Clampin, Mark |date=2013|journal=The Astrophysical Journal|volume=775|issue=1|pages=article id. 56|doi=10.1088/0004-637X/775/1/56|bibcode=2013ApJ...775...56K|arxiv=1305.2222|s2cid=62877509 }}</ref>
}}
{{OrbitboxPlanet disk
| disk = Inner hot disk <!-- centred around 0.1AU (from introduction, first paragraph, of the  Bertrand Mennesson et al. (2013) paper)-->
| periapsis = 0.08
| apoapsis = 0.11
}}
|-
| '''Outer hot disk'''
| colspan="4"| 0.21–0.62 [[Astronomical unit|AU]] ''or'' 0.88–1.08 [[Astronomical unit|AU]]
| —
| —
{{OrbitboxPlanet disk
| disk = 10 AU belt
| periapsis = 8
| apoapsis = 12
}}
{{OrbitboxPlanet disk
| disk = Interbelt dust disk
| periapsis = 35
| apoapsis = 133
}}
{{OrbitboxPlanet disk
| disk = Main belt
| periapsis = 133
| apoapsis = 158
| inclination = −66.1
}}
{{OrbitboxPlanet disk
| disk = Main belt outer halo
| periapsis = 158
| apoapsis = 209
}}
{{Orbitbox end}}

==Fomalhaut B (TW Piscis Austrini)==
{{main|TW Piscis Austrini}}
Fomalhaut forms a binary star with the [[K-type main sequence star|K4-type]] star [[TW Piscis Austrini]] (TW PsA), which lies {{convert|0.28|pc|ly|abbr=off}} away from Fomalhaut, and its space velocity agrees with that of Fomalhaut within {{val|0.1|0.5|u=km/s}}, consistent with being a bound companion. A recent age estimate for TW PsA ({{val|400|70|u=million years}}) agrees very well with the isochronal age for Fomalhaut ({{val|450|40|u=million years}}), further arguing for the two stars forming a physical binary.<ref name="age_mam"/>

The designation TW Piscis Austrini is astronomical nomenclature for a [[variable star]]. Fomalhaut B is a [[flare star]] of the type known as a [[BY Draconis variable]]. It varies slightly in [[apparent magnitude]], ranging from 6.44 to 6.49 over a 10.3 day period. While smaller than the [[Sun]], it is relatively large for a flare star. Most flare stars are red [[stellar classification|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 {{val|1.2|0.7|0.6}} Jupiter masses, and a poorly defined orbital period with an estimate loosely centering around 25 years.<ref name=AstronomicalJournal2019-10-07>{{cite journal | url = https://arxiver.moonhats.com/2019/10/09/the-possible-astrometric-signature-of-a-planetary-mass-companion-to-the-nearby-young-star-tw-piscis-austrini-fomalhaut-b-constraints-from-astrometry-radial-velocities-and-direct-imaging-epa/ | journal = [[Astronomical Journal]] |last1=De Rosa |first1=Robert J. |last2=Esposito |first2=Thomas M. |last3=Hirsch |first3=Lea A. |last4=Nielsen |first4=Eric L. |last5=Marley |first5=Mark S. |last6=Kalas |first6=Paul |last7=Wang |first7=Jason J. |last8=Macintosh |first8=Bruce |title=The Possible Astrometric Signature of a Planetary-mass Companion to the Nearby Young Star TW Piscis Austrini (Fomalhaut B): Constraints from Astrometry, Radial Velocities, and Direct Imaging | date = 7 October 2019 | volume = 158 | issue = 6 | page = 225 | arxiv = 1910.02965 | doi = 10.3847/1538-3881/ab4c9b | bibcode = 2019AJ....158..225D | s2cid = 203902656 | doi-access = free }}</ref>

==Fomalhaut C (LP 876-10)==
{{main|Fomalhaut C}}
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.<ref name="Mamajek2013" /> LP 876-10 was originally catalogued as a high-proper-motion star by [[Willem Luyten]] in his 1979 [[NLTT#Proper motion catalogues|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 (constellation)|Aquarius]], whereas both Fomalhaut A and TW PsA are located in constellation [[Piscis Austrinus]]. Its current separation from Fomalhaut A is about {{convert|0.77|pc|ly|abbr=off}}, and it is currently located {{convert|0.987|pc|ly|abbr=off}} away from TW PsA (Fomalhaut B). LP 876-10 is located well within the tidal radius of the Fomalhaut system, which is {{convert|1.9|pc|ly|abbr=off}}.<ref name="Mamajek2013" /> Although LP 876-10 is itself catalogued as a binary star in the [[Washington Double Star Catalog]] (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.<ref name="Mamajek2013" /> 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.<ref name="GMKennedy2013" />

==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]]s, [[Persians]], and [[Chinese people|Chinese]]. It marked the solstice in 2500&nbsp;BC. It was also a marker for the worship of [[Demeter]] in [[Eleusis]].{{refn|{{cite web |title=Solitary Fomalhaut guards the southern sky |quote=Fomalhaut had first visible exoplanet. |date=9 September 2021 |series=Brightest stars |website=earthsky.org |url=http://earthsky.org/brightest-stars/solitary-fomalhaut-guards-the-southern-sky}}, cites [[Richard Hinckley Allen|R.H. Allen]] (1963).<ref name=rhallen/>}}
* It is considered to be one of the four "[[royal stars]]" of the [[Persia]]ns.<ref name=rhallen>{{cite book |first=R.H. |last=Allen |author-link=Richard Hinckley Allen |year=1963 |section=Piscis Australis, the Southern Fish |title=Star Names — Their Lore and Meaning |edition=reprint |pages=344–347 |publisher=Dover Books |url=https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Piscis_Australis*.html |via=Penelope, [[U Chicago]]}}</ref>
* The Latin names are ''{{lang|la|ōs piscis merīdiāni, ōs piscis merīdionālis, ōs piscis notii}}'' "the mouth of the Southern Fish".<ref name=rhallen/>
* A folk name among the early Arabs was ''Difdi' al Awwal'' ({{lang|ar|الضفدع الأول}} ''{{transliteration|ar|al-ḍifdiʿ al-awwal}}'') "the first frog" (the second frog is [[Beta Ceti]]).<ref name=rhallen/>
* The [[Chinese star names|Chinese name]] {{lang|zh|北落師門/北落师门}} ([[Mandarin Chinese|Mandarin]]: 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 (astronomy)|asterism]], [[Encampment (Chinese constellation)|Encampment]] mansion (see: [[Chinese constellation]]s).<ref>{{cite web |script-title=zh:天文教育資訊網 |trans-title=Astronomy Education Information Network |date=7 July 2006 |language=zh |series=Activities of Exhibition and Education in Astronomy (AEEA) |url=http://aeea.nmns.edu.tw/2006/0607/ap060707.html |access-date=24 August 2012 |archive-date=21 May 2011 |archive-url=https://web.archive.org/web/20110521232711/http://aeea.nmns.edu.tw/2006/0607/ap060707.html }}</ref> {{lang|zh|北落师门}} (Běiluòshīmén), westernized into ''Pi Lo Sze Mun'' by R.H. Allen.<ref name=rhallen/>
* To the Moporr Aboriginal people of South Australia, it is a male being called ''Buunjill''.<ref>{{cite book |last=Dawson |first=James |date=1881 |title=Australian Aborigines |publisher=George Robertson |location=Sydney, AU |isbn=0-85575-118-5 |url=https://archive.org/details/McGillLibrary-rbsc_australian-aborigines_QUARTO-2506-17783 |page=[https://archive.org/details/McGillLibrary-rbsc_australian-aborigines_QUARTO-2506-17783/page/n113 100] }}</ref> The [[Wardaman people]] of the Northern Territory called Fomalhaut ''Menggen'' —white cockatoo.<ref>{{cite book |last1 = Harney |first1 = Bill Yidumduma |last2 = Cairns |first2 = Hugh C. |year = 2004 |orig-date = 2003 |title = Dark Sparklers |publisher = Hugh C. Cairns |location = Merimbula, New South Wales |edition = revised |isbn = 0-9750908-0-1 |page=204}}</ref>

Fomalhaut-Earthwork&nbsp;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 [[Medicine Wheel/Medicine Mountain National Historic Landmark|Bighorn medicine wheel]] in Wyoming, USA, and the [[Moose Mountain Upland|Moose Mountain]] [[medicine wheel]] in Saskatchewan, Canada.<ref>{{cite journal | last=Robinson | first=J.H. |date=September 1980 | title=Fomalhaut and cairn&nbsp;D at the Big Horn and Moose Mountain medicine wheels | journal=Bulletin of the Astronomical Society | volume=12 | page=887 | bibcode=1980BAAS...12..887R }}</ref>

[[New Scientist|''New Scientist'' magazine]] termed it the "Great [[Eye of Sauron]]", comparing its shape and debris ring to the aforementioned "eye" in the [[Peter Jackson]] ''[[The Lord of the Rings (film series)|Lord of the Rings]]'' films.<ref>{{cite news |author=Semeniuk, Ivan |date=22 June 2005 |title=Hubble spies lord of the stellar rings |magazine=[[New Scientist]] |url=https://www.newscientist.com/article/dn7564-hubble-spies-lord-of-the-stellar-rings.html}}</ref>

[[USS Fomalhaut (AK-22)|USS ''Fomalhaut'' (AK-22)]] was a [[United States]] navy [[amphibious cargo ship]].<ref>{{cite web |title=Attack cargo ship ''Fomalhaut'' (AE-20) |date=2005-10-02 |df=dmy-all |website=navsource.org |url=http://www.navsource.org/archives/10/02/02005.htm |access-date=2020-01-25 }}</ref>

==See also==
* [[Exoasteroid]]
* [[2M1207]]
* [[Gliese 758|GJ 758]]
* [[HR 8799]]
* [[Methods of detecting extrasolar planets#Direct imaging|Direct imaging of extrasolar planets]]
* [[Lists of exoplanets]]
* [[List of star systems within 25–30 light-years]]
*

==Notes==
{{Reflist|group="nb"|refs=

<ref name=metal group=nb>Calculation of [[metallicity#Calculation|metallicity]]: if ''m'' = [Fe/H], then the ratio of iron to hydrogen for Fomalhaut divided by the ratio of iron to hydrogen for the Sun is given by 10<sup>''m''</sup>.</ref>
}}

==References==
{{Reflist|refs=

<ref name="SIMBAD">{{cite web
  | title=V* TW PsA – Variable of BY Dra type | work=SIMBAD
  | publisher=Centre de Données astronomiques de Strasbourg
  | url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=GJ+879&submit=SIMBAD+search
  | access-date=2010-01-20 }}</ref>

<ref name=ducati>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|page=0|last1=Ducati|first1=J. R.|year=2002}}</ref>

<ref name="clpl4">{{cite journal
 |author1=Johnson, H. L. |author2=Iriarte, B. |author3=Mitchell, R. I. |author4=Wisniewskj, W. Z. | title=UBVRIJKL photometry of the bright stars
 | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | page=99
 | date=1966
 | bibcode=1966CoLPL...4...99J }}</ref>

<ref name=age_mam>{{Cite journal | last1=Mamajek | first1=E.E. | title=On the Age and Binarity of Fomalhaut | journal=Astrophysical Journal Letters | volume=754 | issue=2 |date=August 2012 | pages=L20 | doi=10.1088/2041-8205/754/2/L20 | arxiv=1206.6353| s2cid=119191190 |bibcode=2012ApJ...754L..20M }}</ref>

<ref name=aaa474_2_653>{{Cite journal | last1=van Leeuwen | first1=F. | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 |date=November 2007 | pages=653–664 | doi=10.1051/0004-6361:20078357 | bibcode=2007A&A...474..653V | arxiv=0708.1752| s2cid=18759600 }}</ref>

<ref name=GSM>{{cite book| last=Perryman | first=Michael | title=The Making of History's Greatest Star Map | location=Heidelberg | publisher=Springer-Verlag | date=2010 | doi=10.1007/978-3-642-11602-5| series=Astronomers' Universe | isbn=978-3-642-11601-8 | bibcode=2010mhgs.book.....P | url=https://cds.cern.ch/record/1338896 }}</ref>

<ref name=mnras286_3>{{cite journal | title=High-resolution spectroscopy of Vega-like stars - I. Effective temperatures, gravities and photospheric abundances | author1=Dunkin, S. K. | author2=Barlow, M. J. | author3=Ryan, Sean G. | journal=Monthly Notices of the Royal Astronomical Society | volume=286 | issue=3 | pages=604–616 |date=April 1997 | bibcode=1997MNRAS.286..604D | doi=10.1093/mnras/286.3.604| doi-access=free }} This paper lists [Fe/H] = −0.03 [[wikt:dex|dex]].</ref>

<ref name=apj475>{{cite journal |author1=Barrado y Navascues, David |author2=Stauffer, John R. |author3=Hartmann, Lee |author4=Balachandran, Suchitra C. | title=The Age of Gliese 879 and Fomalhaut | journal=Astrophysical Journal | volume=475 |issue=1 | page=313 |date=January 1997 | doi=10.1086/303518 | bibcode=1997ApJ...475..313B |arxiv = astro-ph/9704021 |s2cid=15434275 }} This paper lists [Fe/H] = −0.11 dex.</ref>

<ref name=aaa426>{{cite journal | title=VLTI near-IR interferometric observations of Vega-like stars. Radius and age of α PsA, β Leo, β Pic, ɛ Eri and τ Cet |author1=Di Folco, E. |author2=Thévenin, F. |author3=Kervella, P. |author4=Domiciano de Souza, A. |author5=Coudé du Foresto, V. |author6=Ségransan, D. |author7=Morel, P. | journal=Astronomy and Astrophysics | volume=426 | pages=601–617 |date=November 2004 | doi=10.1051/0004-6361:20047189 | bibcode=2004A&A...426..601D | issue=2 |doi-access=free }} This paper lists [Fe/H] = −0.10 dex.</ref>

<ref name=aaa490_1>{{cite journal |author1=Saffe, C. |author2=Gómez, M. |author3=Pintado, O. |author4=González, E. | title=Spectroscopic metallicities of Vega-like stars | journal=Astronomy and Astrophysics | volume=490 | issue=1 | pages=297–305 |date=October 2008 | doi=10.1051/0004-6361:200810260 | bibcode=2008A&A...490..297S |arxiv = 0805.3936 |s2cid=15059920 }} This paper lists [Fe/H] = −0.34 dex.</ref>

<ref name="Kalas2008">{{cite journal | last=Kalas | first=Paul |display-authors=etal | date=2008 | title=Optical Images of an Exosolar Planet 25 Light-Years from Earth | journal=Science | volume=322 | issue=5906 | pages=1345–1348 | doi=10.1126/science.1166609 | pmid=19008414 |bibcode = 2008Sci...322.1345K |arxiv = 0811.1994 | s2cid=10054103 }}</ref>

<ref name="age">{{cite journal | author=Barrado y Navascues, D. | title=The Castor moving group. The age of Fomalhaut and VEGA | journal=Astronomy and Astrophysics | volume=339 | pages=831–839 | date=1998 | bibcode=1998A&A...339..831B |arxiv = astro-ph/9905243 }}</ref>

<ref name="lifespan">{{cite news | title=Elusive Planet Reshapes a Ring Around Neighboring Star | publisher=Space Telescope Science Institute (STScI) | url=http://hubblesite.org/newscenter/archive/releases/2005/10/ | date=June 22, 2005 | work=HubbleSite - newscenter }}</ref>

<ref name=nature435_7045_1067>{{cite journal | last=Kalas | first=Paul |author2=Graham, James R. |author3=Clampin, Mark | date=2005 | title=A planetary system as the origin of structure in Fomalhaut's dust belt | journal=[[Nature (journal)|Nature]] | pmid=15973402 | volume=435 | issue=7045 | pages=1067–1070 | doi=10.1038/nature03601| arxiv=astro-ph/0506574 | bibcode=2005Natur.435.1067K| s2cid=4406070 }}</ref>

<ref name=nature392_6678_788>The disc was reported by {{cite journal | last=Holland | first=Wayne S. | display-authors=etal | date=1998 | title=Submillimetre images of dusty debris around nearby stars | journal=Nature | volume=392 | issue=6678 | pages=788–791 | doi=10.1038/33874 | bibcode=1998Natur.392..788H| s2cid=4373502 }} They noted that the disc was centered on a cavity, which they suggested might have been swept out by planets.</ref>

<ref name=baas25_1319>{{cite journal | last1=Garrison | first1=R. F. | title=Anchor Points for the MK System of Spectral Classification | journal=Bulletin of the American Astronomical Society | volume=25 | page=1319 | date=December 1993 | bibcode=1993AAS...183.1710G | url=http://www.astro.utoronto.ca/~garrison/mkstds.html | access-date=2012-02-04 | archive-date=2019-06-25 | archive-url=https://web.archive.org/web/20190625094716/http://www.astro.utoronto.ca/~garrison/mkstds.html }}</ref>

<ref name="Mamajek2013">{{cite journal  |last1=Mamajek |first1=Eric E.   |title=The Solar Neighborhood. XXX. Fomalhaut C  |year=2013  |journal=[[The Astronomical Journal]]  |volume=146 | issue=6 | page=154  |arxiv=1310.0764  |doi=10.1088/0004-6256/146/6/154  |bibcode=2013AJ....146..154M|last2=Bartlett  |first2=Jennifer L. |author2-link=Jennifer Bartlett (astronomer) |last3=Seifahrt  |first3=Andreas  |last4=Henry  |first4=Todd J.  |last5=Dieterich  |first5=Sergio B.  |last6=Lurie  |first6=John C.  |last7=Kenworthy  |first7=Matthew A.  |last8=Jao  |first8=Wei-Chun  |last9=Riedel  |first9=Adric R.  |last10=Subasavage  |first10=John P.  |last11=Winters  |first11=Jennifer G.  |last12=Finch  |first12=Charlie T.  |last13=Ianna  |first13=Philip A.  |last14=Bean  |first14=Jacob  |s2cid=67821813 }}</ref>

<ref name=GMKennedy2013>{{cite journal
  |date=2013-12-17
  |title=Discomapvery of the Fomalhaut C debris disc  |journal=[[Monthly Notices of the Royal Astronomical Society]]
  |last1=Kennedy |first1=Grant M. |last2=Wyatt |first2= M.C. |last3=Kalas |first3=P. |last4=Duchêne |first4=G. |last5=Sibthorpe |first5=B. |last6=Lestrade |first6=J.-F. |last7=Matthews |first7=B.C. |last8=Greaves |first8=G.
  |display-authors=1<!--Expandable-->
  |arxiv=1312.5315
  |bibcode=2014MNRAS.438L..96K
  |doi=10.1093/mnrasl/slt168 |volume=438 |issue=1 |pages=L96–L100|doi-access=free |s2cid=53600511 }}</ref>

<ref name=skyandtelescope2014-10-01>
{{cite news    
| url         = https://skyandtelescope.org/astronomy-news/fomalhaut-falls-amazing-triple-star10012014/
| title       = Fomalhaut: A crazy-wide triple stat
| work        = [[Sky & Telescope]]
| author      = Bob King
| date        = 2014-10-01
| access-date  = 2020-06-13
| quote       = When you next look at Fomalhaut twinkling above the fall leaves, put four fingers together and hold them up against the sky. They'll cover about 8°, or the amount of real estate spanned by the triple system. <!-- Though it may appear isolated in the barren October sky, Fomalhaut has company. It feels the gravitational tug of the magnitude +6.5 star TW Piscis Austrini, 2° to the south. Both are 25 light-years distant and move in tandem across space, partaking of the same proper motion. They form a true double star with an actual separation of 5.5 trillion miles, or 0.91 light-years. -->
}}
</ref>

<ref name="gaspar20newhst">{{Cite journal
|title=New HST data and modeling reveal a massive planetesimal collision around Fomalhaut
|author1=András Gáspár|author2=George H. Rieke
|journal=Proceedings of the National Academy of Sciences
|volume=117|issue=18|pages=9712–9722|date=2020-05-05
|doi=10.1073/pnas.1912506117|pmid=32312810 |pmc=7211925 |doi-access=free
|arxiv=2004.08736|bibcode=2020PNAS..117.9712G
}}</ref>

<ref name="Gaspar2023">{{cite journal |last1=Gáspár |first1=András |last2=Wolff |first2=Schuyler Grace |display-authors=etal |title=Spatially resolved imaging of the inner Fomalhaut disk using JWST/MIRI |url=https://www.nature.com/articles/s41550-023-01962-6 |date=8 May 2023 |journal=[[Nature Astronomy]] |volume= 7|issue=7 |pages=790–798 |doi=10.1038/s41550-023-01962-6 |arxiv=2305.03789 |bibcode=2023NatAs...7..790G |s2cid=258558003 |access-date=8 May 2023 }}</ref>

<ref name="Kennedy2023">{{cite journal |last1=Kennedy |first1=Grant M. |last2=Lovell |first2=Joshua B. |display-authors=etal |date=May 2023 |title=ALMA and Keck analysis of Fomalhaut field sources: JWST's Great Dust Cloud is a background object |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume= 524|issue= 2|pages= 2698–2704|doi= 10.1093/mnras/stad2058|doi-access=free |arxiv=2305.10480}}</ref>

<ref name="Ygouf2023">{{cite journal |last1=Ygouf |first1=Marie |last2=Beichman |first2=Charles |display-authors=etal |title=Searching for Planets Orbiting Fomalhaut with JWST/NIRCam |journal=The Astronomical Journal |date=October 2023 |volume=167 |issue=1 |page=26 |doi=10.3847/1538-3881/ad08c8 |doi-access=free |arxiv=2310.15028 |bibcode=2024AJ....167...26Y }}</ref>

<ref name="Gray2006">{{cite journal |last1=Gray |first1=R. O. |last2=Corbally |first2=C. J. |display-authors=etal |date=July 2006 |title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample |journal=[[The Astronomical Journal]] |volume=132 |issue=1 |pages=161–170 |doi=10.1086/504637 |arxiv=astro-ph/0603770 |bibcode=2006AJ....132..161G|s2cid=250741593 }}</ref>

}}

==External links==
{{Commons category}}
* {{cite web |
 title=Fomalhaut |
 work=SolStation |
 url=http://www.solstation.com/stars/fomalhau.htm |
 access-date=November 23, 2005}}
* [https://web.archive.org/web/20121012232318/http://astrobites.com/2012/04/15/almas-first-results-tackle-the-controversial-fomalhaut/ Astrobites summary of Boley et al. 2012, the ALMA observations of the Fomalhaut ring system]
* [https://web.archive.org/web/20130113152320/http://www.thelivingmoon.com/41pegasus/02files/Eye_of_Sauron.html "Eye of Sauron" debris ring]
* [http://www.astronomy.com/news/2013/10/researchers-find-that-bright-nearby-double-star-fomalhaut-is-actually-a-triple Researchers find that bright nearby double star Fomalhaut is actually a triple] (Astronomy magazine : October 8, 2013)

{{Sky|22|57|39.1|-|29|37|20|25}}
{{Stars of Piscis Austrinus}}
{{Portal bar|Astronomy|Stars|Outer space}}
{{Fomalhaut}}

<!-- Properties -->

{{DEFAULTSORT:Fomalhaut}}
[[Category:Fiction set around Fomalhaut|Fiction set around Fomalhaut]]
[[Category:A-type main-sequence stars]]
[[Category:Triple star systems]]
[[Category:Multi-star planetary systems|3]]
[[Category:M-type main-sequence stars]]
[[Category:K-type main-sequence stars]]
[[Category:BY Draconis variables]]
[[Category:Hypothetical planetary systems]]
[[Category:Circumstellar disks]]
[[Category:Castor Moving Group]]
<!-- Position/catalogues -->
[[Category:Piscis Austrinus]]
[[Category:Bayer objects|Piscis Austrini, Alpha]]
[[Category:Bright Star Catalogue objects|8728]]
[[Category:Durchmusterung objects]]
[[Category:Flamsteed objects|Piscis Austrini, 24]]
[[Category:Gliese and GJ objects|0879 81]]
[[Category:Henry Draper Catalogue objects|216956]]
[[Category:Hipparcos objects|113368]]
[[Category:Arabic words and phrases]]
[[Category:Fomalhaut| ]]
[[Category:Stars with proper names|Fomalhaut]]