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{{short description|Constellation in the southern celestial hemisphere}}
{{short description|Constellation in the southern celestial hemisphere}}
{{about|a constellation of stars|the Roman goddess|Fornax (mythology)}}
{{about|the constellation |the Roman goddess|Fornax (mythology)}}


{{Infobox constellation
{{Infobox constellation
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The three brightest stars—[[Alpha Fornacis|Alpha]], [[Beta Fornacis|Beta]] and [[Nu Fornacis]]—form a flattened triangle facing south. With an apparent magnitude of 3.91, Alpha Fornacis is the brightest star in Fornax. Six star systems have been found to have exoplanets. The [[Fornax Dwarf]] galaxy is a small faint satellite galaxy of the [[Milky Way]]. [[NGC 1316]] is a relatively close [[radio galaxy]].
The three brightest stars—[[Alpha Fornacis|Alpha]], [[Beta Fornacis|Beta]] and [[Nu Fornacis]]—form a flattened triangle facing south. With an apparent magnitude of 3.91, Alpha Fornacis is the brightest star in Fornax. Six star systems have been found to have exoplanets. The [[Fornax Dwarf]] galaxy is a small faint satellite galaxy of the [[Milky Way]]. [[NGC 1316]] is a relatively close [[radio galaxy]].

The [[Hubble Space Telescope|Hubble]]'s [[Hubble Ultra-Deep Field|Ultra-Deep Field]] is located within the Fornax constellation.<ref>{{Cite web |title=Hubble Ultra Deep Field |url=https://hubblesite.org/contents/media/images/3886-Image |access-date=February 2, 2024 |website=hubblesite.org}}</ref>


It is the 41st largest [[constellation]] in the [[Night sky|night-sky]], occupying an area of 398 [[Square degree|square degrees.]] It is located in the first quadrant of the [[Southern Hemisphere|southern hemisphere]] (SQ1) and can be seen at [[Latitude|latitudes]] between +50° and -90° during the month of December.
It is the 41st largest [[constellation]] in the [[Night sky|night-sky]], occupying an area of 398 [[Square degree|square degrees.]] It is located in the first quadrant of the [[Southern Hemisphere|southern hemisphere]] (SQ1) and can be seen at [[Latitude|latitudes]] between +50° and -90° during the month of December.
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[[File:Sidney Hall - Urania's Mirror - Psalterium Georgii, Fluvius Eridanus, Cetus, Officina Sculptoris, Fornax Chemica, and Machina Electrica.jpg|thumb|left|350px|Fornax Chemica can be seen below [[Cetus (constellation)|Cetus]] in this card from ''[[Urania's Mirror]]'' (1825).]]
[[File:Sidney Hall - Urania's Mirror - Psalterium Georgii, Fluvius Eridanus, Cetus, Officina Sculptoris, Fornax Chemica, and Machina Electrica.jpg|thumb|left|350px|Fornax Chemica can be seen below [[Cetus (constellation)|Cetus]] in this card from ''[[Urania's Mirror]]'' (1825).]]


The French astronomer [[Nicolas Louis de Lacaille]] first described the [[constellation]] in French as ''le Fourneau Chymique'' (the Chemical Furnace) with an [[alembic]] and receiver in his early catalogue,<ref name=wagman/> before abbreviating it to ''le Fourneau'' on his planisphere in 1752,<ref name=ridpathlac>{{cite web |url=http://www.ianridpath.com/startales/lacaille.htm |title=Lacaille's Southern Planisphere of 1756 |work=Star Tales |author=Ridpath, Ian |publisher=Self-published |access-date=7 November 2016|author-link=Ian Ridpath }}</ref><ref>{{cite journal |author=Lacaille, Nicolas Louis |year=1756 |title=Relation abrégée du Voyage fait par ordre du Roi au cap de Bonne-espérance |journal=Mémoires de l'Académie Royale des Sciences |pages=519–592 [588] |url=http://gallica.bnf.fr/ark:/12148/bpt6k35505/f786 |language=fr}}</ref> after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the [[Cape of Good Hope]]. He devised fourteen new constellations in uncharted regions of the [[Southern Celestial Hemisphere]] not visible from Europe. All but one honoured instruments that symbolised the [[Age of Enlightenment]].{{efn|1=The exception is [[Mensa (constellation)|Mensa]], named for the [[Table Mountain]]. The other thirteen (alongside Fornax) are [[Antlia]], [[Caelum]], [[Circinus]], [[Horologium (constellation)|Horologium]], [[Microscopium]], [[Norma (constellation)|Norma]], [[Octans]], [[Pictor]], [[Pyxis]], [[Reticulum]], [[Sculptor (constellation)|Sculptor]] and [[Telescopium]].<ref name=wagman/>}} Lacaille Latinised the name to ''Fornax Chimiae'' on his 1763 chart.<ref name=wagman>{{cite book |last=Wagman |first=Morton |date=2003 |title=Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others |publisher=The McDonald & Woodward Publishing Company |location=Blacksburg, Virginia |isbn=978-0-939923-78-6 |pages=6–7, 152}}</ref><!-- Cites previous three sentences -->
The French astronomer [[Nicolas Louis de Lacaille]] first described the [[constellation]] in French as ''le Fourneau Chymique'' (the Chemical Furnace) with an [[alembic]] and receiver in his early catalogue,<ref name=wagman/> before abbreviating it to ''le Fourneau'' on his planisphere in 1752,<ref name=ridpathlac>{{cite web |url=http://www.ianridpath.com/startales/lacaille.html |title=Lacaille's Southern Planisphere of 1756 |work=Star Tales |author=Ridpath, Ian |publisher=Self-published |access-date=7 November 2016|author-link=Ian Ridpath }}</ref><ref>{{cite journal |author=Lacaille, Nicolas Louis |year=1756 |title=Relation abrégée du Voyage fait par ordre du Roi au cap de Bonne-espérance |journal=Mémoires de l'Académie Royale des Sciences |pages=519–592 [588] |url=http://gallica.bnf.fr/ark:/12148/bpt6k35505/f786 |language=fr}}</ref> after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the [[Cape of Good Hope]]. He devised fourteen new constellations in uncharted regions of the [[Southern Celestial Hemisphere]] not visible from Europe. All but one honoured instruments that symbolised the [[Age of Enlightenment]].{{efn|1=The exception is [[Mensa (constellation)|Mensa]], named for the [[Table Mountain]]. The other thirteen (alongside Fornax) are [[Antlia]], [[Caelum]], [[Circinus]], [[Horologium (constellation)|Horologium]], [[Microscopium]], [[Norma (constellation)|Norma]], [[Octans]], [[Pictor]], [[Pyxis]], [[Reticulum]], [[Sculptor (constellation)|Sculptor]] and [[Telescopium]].<ref name=wagman/>}} Lacaille Latinised the name to ''Fornax Chimiae'' on his 1763 chart.<ref name=wagman>{{cite book |last=Wagman |first=Morton |date=2003 |title=Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others |publisher=The McDonald & Woodward Publishing Company |location=Blacksburg, Virginia |isbn=978-0-939923-78-6 |pages=6–7, 152}}</ref><!-- Cites previous three sentences -->


{{clear|left}}
{{clear|left}}
==Characteristics==
==Characteristics==
The constellation Eridanus borders Fornax to the east, north and south, while Cetus, Sculptor and Phoenix gird it to the north, west and south respectively. Covering 397.5&nbsp;square degrees and 0.964% of the night sky, it ranks 41st of the 88 constellations in size,<ref name=tirionconst>{{cite web| url=http://www.ianridpath.com/constellations1.htm | title=Constellations: Andromeda–Indus | work= Star Tales |author= Ridpath, Ian |author-link = Ian Ridpath |publisher=Self-published | access-date= 7 November 2016}}</ref> The three-letter abbreviation for the constellation, as adopted by the [[International Astronomical Union]] in 1922, is "For".<ref name="pa30_469">{{cite journal | last=Russell | first=Henry Norris |author-link=Henry Norris Russell | title=The New International Symbols for the Constellations | journal=[[Popular Astronomy (US magazine)|Popular Astronomy]] | volume=30 | page=469 | bibcode=1922PA.....30..469R | date=1922}}</ref> The official constellation boundaries, as set by Belgian astronomer [[Eugène Joseph Delporte|Eugène Delporte]] in 1930, are defined by a polygon of 8 segments (''illustrated in infobox''). In the [[equatorial coordinate system]], the [[right ascension]] coordinates of these borders lie between {{RA|01|45|24.18}} and {{RA|03|50|21.34}}, while the [[declination]] coordinates are between −23.76° and −39.58°.<ref name="boundary">{{Cite journal | title=Fornax, Constellation Boundary | journal=The Constellations | publisher=International Astronomical Union | url=http://www.iau.org/public/constellations/#for| access-date=7 November 2016}}</ref> The whole constellation is visible to observers south of latitude [[50th parallel north|50°N]].{{efn|1=While parts of the constellation technically rise above the horizon to observers between 50°N and [[66th parallel north|66°N]], stars within a few degrees of the horizon for to all intents and purposes unobservable.<ref name=tirionconst/>}}
The constellation Eridanus borders Fornax to the east, north and south, while Cetus, Sculptor and Phoenix gird it to the north, west and south respectively. Covering 397.5&nbsp;square degrees and 0.964% of the night sky, it ranks 41st of the 88 constellations in size,<ref name=tirionconst>{{cite web| url=http://www.ianridpath.com/constellations1.html | title=Constellations: Andromeda–Indus | work= Star Tales |author= Ridpath, Ian |author-link = Ian Ridpath |publisher=Self-published | access-date= 7 November 2016}}</ref> The three-letter abbreviation for the constellation, as adopted by the [[International Astronomical Union]] in 1922, is "For".<ref name="pa30_469">{{cite journal | last=Russell | first=Henry Norris |author-link=Henry Norris Russell | title=The New International Symbols for the Constellations | journal=[[Popular Astronomy (US magazine)|Popular Astronomy]] | volume=30 | page=469 | bibcode=1922PA.....30..469R | date=1922}}</ref> The official constellation boundaries, as set by Belgian astronomer [[Eugène Joseph Delporte|Eugène Delporte]] in 1930, are defined by a polygon of 8 segments (''illustrated in infobox''). In the [[equatorial coordinate system]], the [[right ascension]] coordinates of these borders lie between {{RA|01|45|24.18}} and {{RA|03|50|21.34}}, while the [[declination]] coordinates are between −23.76° and −39.58°.<ref name="boundary">{{Cite journal | title=Fornax, Constellation Boundary | journal=The Constellations | publisher=International Astronomical Union | url=https://www.iau.org/public/themes/constellations/#for| access-date=7 November 2016}}</ref> The whole constellation is visible to observers south of latitude [[50th parallel north|50°N]].{{efn|1=While parts of the constellation technically rise above the horizon to observers between 50°N and [[66th parallel north|66°N]], stars within a few degrees of the horizon for to all intents and purposes unobservable.<ref name=tirionconst/>}}


==Features==
==Features==
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===Stars===
===Stars===
{{see also|List of stars in Fornax}}
{{see also|List of stars in Fornax}}
Lacaille gave [[Bayer designation]]s to 27 stars now named Alpha to Omega Fornacis, labelling two stars 3.5 degrees apart as Gamma, three stars Eta, two stars Iota, two Lambda and three Chi. Phi Fornacis was added by Gould, and Theta and Omicron were dropped by Gould and Baily respectively. Upsilon, too, was later found to be two stars and designated as such.<ref name=wagman/> Overall, there are 59 stars within the constellation's borders brighter than or equal to [[apparent magnitude]] 6.5.{{efn|1=Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies.<ref>{{cite web|url=http://www.skyandtelescope.com/resources/darksky/3304011.html?page=1&c=y|title=The Bortle Dark-Sky Scale|last=Bortle|first=John E.|date=February 2001|work=[[Sky & Telescope]]|publisher=Sky Publishing Corporation|access-date=7 November 2016|archive-date=31 March 2014|archive-url=https://web.archive.org/web/20140331202746/http://www.skyandtelescope.com/resources/darksky/3304011.html?page=1&c=y|url-status=dead}}</ref>}}<ref name=tirionconst/> However, there are no stars brighter than the fourth magnitude.<ref name=tirionfor>{{cite web| url=http://www.ianridpath.com/startales/fornax.htm | title=Fornax | work= Star Tales |author= Ridpath, Ian |author-link = Ian Ridpath |publisher=Self-published | access-date= 7 November 2016}}</ref>
Lacaille gave [[Bayer designation]]s to 27 stars now named Alpha to Omega Fornacis, labelling two stars 3.5 degrees apart as Gamma, three stars Eta, two stars Iota, two Lambda and three Chi. Phi Fornacis was added by Gould, and Theta and Omicron were dropped by Gould and Baily respectively. Upsilon, too, was later found to be two stars and designated as such.<ref name=wagman/> Overall, there are 59 stars within the constellation's borders brighter than or equal to [[apparent magnitude]] 6.5.{{efn|1=Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies.<ref>{{cite web|url=http://www.skyandtelescope.com/resources/darksky/3304011.html?page=1&c=y|title=The Bortle Dark-Sky Scale|last=Bortle|first=John E.|date=February 2001|work=[[Sky & Telescope]]|publisher=Sky Publishing Corporation|access-date=7 November 2016|archive-date=31 March 2014|archive-url=https://web.archive.org/web/20140331202746/http://www.skyandtelescope.com/resources/darksky/3304011.html?page=1&c=y|url-status=dead}}</ref>}}<ref name=tirionconst/> However, there are no stars brighter than the fourth magnitude.<ref name=tirionfor>{{cite web| url=http://www.ianridpath.com/startales/fornax.html | title=Fornax | work= Star Tales |author= Ridpath, Ian |author-link = Ian Ridpath |publisher=Self-published | access-date= 7 November 2016}}</ref>


The three brightest stars form a flattish triangle, with [[Alpha Fornacis|Alpha]] (also called Dalim<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=30 July 2018}}</ref>) and [[Nu Fornacis]] marking its eastern and western points and [[Beta Fornacis]] marking the shallow southern apex.<ref>{{cite book |last=Thompson |first=Mark |title=A Down to Earth Guide to the Cosmos |publisher=Random House |date=2013 |isbn=978-1-4481-2691-0 |url=https://books.google.com/books?id=SOfRFJBy-igC&pg=PT132|page=132}}</ref> Originally designated 12 Eridani by John Flamsteed, Alpha Fornacis was named by Lacaille as the brightest star in the new constellation.<ref name=wagman/> It is a binary star that can be resolved by small amateur telescopes. With an apparent magnitude of 3.91, the primary is a yellow-white subgiant 1.21 times as massive as the Sun that has begun to cool and expand after exhausting its core hydrogen, having swollen to 1.9 times the Sun's radius. Of magnitude 6.5, the secondary star is 0.78 times as massive as the Sun. It has been identified as a [[blue straggler]], and has either accumulated material from, or merged with, a third star in the past. It is a strong source of X-rays.<ref name=Fuhrmann2015>{{cite journal | last1=Fuhrmann | first1=K. | last2=Chini | first2=R. | title=Multiplicity among F-type Stars. II | journal=The Astrophysical Journal | volume=809 | issue=1 | id=107 | pages=19 | date=2015 | doi=10.1088/0004-637X/809/1/107 | bibcode=2015ApJ...809..107F | doi-access=free }}</ref> The pair is 46.4 ± 0.3 light-years distant from Earth.<ref name="vanLeeuwen2007">{{cite journal | first=F. | last=van Leeuwen | title=Validation of the New Hipparcos Reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–64 | date=2007 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | arxiv=0708.1752| s2cid=18759600 }}</ref>
The three brightest stars form a flattish triangle, with [[Alpha Fornacis|Alpha]] (also called Dalim<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=30 July 2018}}</ref>) and [[Nu Fornacis]] marking its eastern and western points and [[Beta Fornacis]] marking the shallow southern apex.<ref>{{cite book |last=Thompson |first=Mark |title=A Down to Earth Guide to the Cosmos |publisher=Random House |date=2013 |isbn=978-1-4481-2691-0 |url=https://books.google.com/books?id=SOfRFJBy-igC&pg=PT132|page=132}}</ref> Originally designated 12 Eridani by John Flamsteed, Alpha Fornacis was named by Lacaille as the brightest star in the new constellation.<ref name=wagman/> It is a binary star that can be resolved by small amateur telescopes. With an apparent magnitude of 3.91, the primary is a yellow-white subgiant 1.21 times as massive as the Sun that has begun to cool and expand after exhausting its core hydrogen, having swollen to 1.9 times the Sun's radius. Of magnitude 6.5, the secondary star is 0.78 times as massive as the Sun. It has been identified as a [[blue straggler]], and has either accumulated material from, or merged with, a third star in the past. It is a strong source of X-rays.<ref name=Fuhrmann2015>{{cite journal | last1=Fuhrmann | first1=K. | last2=Chini | first2=R. | title=Multiplicity among F-type Stars. II | journal=The Astrophysical Journal | volume=809 | issue=1 | id=107 | pages=19 | date=2015 | doi=10.1088/0004-637X/809/1/107 | bibcode=2015ApJ...809..107F | doi-access=free }}</ref> The pair is 46.4 ± 0.3 light-years distant from Earth.<ref name="vanLeeuwen2007">{{cite journal | first=F. | last=van Leeuwen | title=Validation of the New Hipparcos Reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–64 | date=2007 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | arxiv=0708.1752| s2cid=18759600 }}</ref>
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[[R Fornacis]] is a long-period variable and carbon star.
[[R Fornacis]] is a long-period variable and carbon star.


[[LP 944-20]] is a [[brown dwarf]] of spectral type M9 that has around 7% the mass of the Sun. Approximately 21 light-years distant from Earth, it is a faint object with an apparent magnitude of 18.69.<ref name="RECONS TOP100">{{cite journal |author=Research Consortium on Nearby Stars |publisher=[[Georgia State University]] |date = 1 January 2012 |title=The 100 nearest star systems |journal=RECONS |url=http://www.astro.gsu.edu/RECONS/TOP100.posted.htm |access-date = 12 February 2017|author-link=Research Consortium on Nearby Stars }}</ref> Observations published in 2007 showed that the atmosphere of LP 944-20 contains much [[lithium]] and that it has dusty [[cloud]]s.<ref>{{ cite journal | title=Lithium in LP944-20 |author1=Pavlenko, Ya. V. |author2=Jones, H. R. A. |author3=Martín, Eduardo L. |author4=Guenther, E. |author5=Kenworthy, M. A. |author6=Zapatero-Osorio, María Rosa | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=380 | issue=3 | pages=1285–96 | date=September 2007 | doi=10.1111/j.1365-2966.2007.12182.x | bibcode=2007MNRAS.380.1285P | arxiv = 0707.0694 |s2cid=11186385 }}</ref> Smaller and less luminous still is [[2MASS J02431371-2453298|2MASS 0243-2453]], a T-type brown dwarf of spectral type T6. With a surface temperature of 1040–1100 [[Kelvin|K]], it has 2.4–4.1% the mass of the Sun, a diameter 9.2 to 10.6% of that of the Sun, and an age of 0.4–1.7 billion years.<ref>{{cite journal | title= Method for Determining the Physical Properties of the Coldest Known Brown Dwarfs |author1=Burgasser, Adam J. |author2=Burrows, Adam |author3=Kirkpatrick, J. Davy |journal=The Astrophysical Journal | volume =639| issue= 2| pages=1095–1113| year=2006 | doi=10.1086/499344 | bibcode=2006ApJ...639.1095B|arxiv = astro-ph/0510707 | s2cid=9291848 }}</ref>
[[LP 944-20]] is a [[brown dwarf]] of spectral type M9 that has around 7% the mass of the Sun. Approximately 21 light-years distant from Earth, it is a faint object with an apparent magnitude of 18.69.<ref name="RECONS TOP100">{{cite journal |author=Research Consortium on Nearby Stars |publisher=[[Georgia State University]] |date = 1 January 2012 |title=The 100 nearest star systems |journal=RECONS |url=http://www.astro.gsu.edu/RECONS/TOP100.posted.htm |access-date = 12 February 2017|author-link=Research Consortium on Nearby Stars }}</ref> Observations published in 2007 showed that the atmosphere of LP 944-20 contains much [[lithium]] and that it has dusty [[cloud]]s.<ref>{{ cite journal | title=Lithium in LP944-20 |author1=Pavlenko, Ya. V. |author2=Jones, H. R. A. |author3=Martín, Eduardo L. |author4=Guenther, E. |author5=Kenworthy, M. A. |author6=Zapatero-Osorio, María Rosa | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=380 | issue=3 | pages=1285–96 | date=September 2007 | doi=10.1111/j.1365-2966.2007.12182.x |doi-access=free | bibcode=2007MNRAS.380.1285P | arxiv = 0707.0694 |s2cid=11186385 }}</ref> Smaller and less luminous still is [[2MASS J02431371-2453298|2MASS 0243-2453]], a T-type brown dwarf of spectral type T6. With a surface temperature of 1040–1100 [[Kelvin|K]], it has 2.4–4.1% the mass of the Sun, a diameter 9.2 to 10.6% of that of the Sun, and an age of 0.4–1.7 billion years.<ref>{{cite journal | title= Method for Determining the Physical Properties of the Coldest Known Brown Dwarfs |author1=Burgasser, Adam J. |author2=Burrows, Adam |author3=Kirkpatrick, J. Davy |journal=The Astrophysical Journal | volume =639| issue= 2| pages=1095–1113| year=2006 | doi=10.1086/499344 | bibcode=2006ApJ...639.1095B|arxiv = astro-ph/0510707 | s2cid=9291848 }}</ref>


Six star systems in Fornax have been found to have planets:
Six star systems in Fornax have been found to have planets:
* [[Lambda2 Fornacis|Lambda<sup>2</sup> Fornacis]] is a star about 1.2 times as massive as the Sun with a planet about as massive as [[Neptune]], discovered by doppler spectroscopy in 2009. The planet has an orbit of around 17.24 days.<ref name="O’Toole2009">{{cite journal | title=A Neptune-mass Planet Orbiting the Nearby G Dwarf HD16417 | last1=O’Toole | first1=Simon | last2=Tinney | first2=C. G. | last3=Butler | first3=R. Paul | last4=Jones | first4=Hugh R. A. | last5=Bailey | first5=Jeremy | last6=Carter | first6=Brad D. | last7=Vogt | first7=Steven S. | last8=Laughlin | first8=Gregory | last9=Rivera | first9=Eugenio J. | journal=The Astrophysical Journal | volume=697 | issue=2 | pages=1263–1268 | date=2009 | arxiv=0902.4024 | bibcode=2009ApJ...697.1263O | doi=10.1088/0004-637X/697/2/1263 | s2cid=16341718 }}</ref>
* [[Lambda2 Fornacis|Lambda<sup>2</sup> Fornacis]] is a star about 1.2 times as massive as the Sun with a planet about as massive as [[Neptune]], discovered by doppler spectroscopy in 2009. The planet has an orbit of around 17.24 days.<ref name="O’Toole2009">{{cite journal | title=A Neptune-mass Planet Orbiting the Nearby G Dwarf HD16417 | last1=O’Toole | first1=Simon | last2=Tinney | first2=C. G. | last3=Butler | first3=R. Paul | last4=Jones | first4=Hugh R. A. | last5=Bailey | first5=Jeremy | last6=Carter | first6=Brad D. | last7=Vogt | first7=Steven S. | last8=Laughlin | first8=Gregory | last9=Rivera | first9=Eugenio J. | journal=The Astrophysical Journal | volume=697 | issue=2 | pages=1263–1268 | date=2009 | arxiv=0902.4024 | bibcode=2009ApJ...697.1263O | doi=10.1088/0004-637X/697/2/1263 | s2cid=16341718 }}</ref>
* [[HD 20868]] is an orange dwarf with a mass around 78% that of the Sun, 151 ± 10 light-years away from Earth. It was found to have an orbiting planet approximately double the mass of Jupiter with a period of 380 days.<ref name="Moutou2009">{{cite journal | title=The HARPS search for southern extra-solar planets XVII. Six long-period giant planets around BD -17 0063, HD 20868, HD 73267, HD 131664, HD 145377, HD 153950 | url=http://www.aanda.org/articles/aa/full_html/2009/11/aa10941-08/aa10941-08.html | last1=Moutou | first1=C. | last2=Mayor | first2=M. | last3=Lo Curto | first3=G. | last4=Udry | first4=S. | last5=Bouchy | first5=F. | last6=Benz | first6=W. | last7=Lovis | first7=C. | last8=Naef | first8=D. | last9=Pepe | first9=F. | last10=Queloz | first10=D. | last11=Santos | first11=N. C. | journal=Astronomy and Astrophysics | volume=496 | issue=2 | pages=513–19 | date=2009 | arxiv=0810.4662 | bibcode=2009A&A...496..513M | doi=10.1051/0004-6361:200810941 }}</ref>
* [[HD 20868]] is an orange dwarf with a mass around 78% that of the Sun, 151 ± 10 light-years away from Earth. It was found to have an orbiting planet approximately double the mass of Jupiter with a period of 380 days.<ref name="Moutou2009">{{cite journal | title=The HARPS search for southern extra-solar planets XVII. Six long-period giant planets around BD -17 0063, HD 20868, HD 73267, HD 131664, HD 145377, HD 153950 | url=http://www.aanda.org/articles/aa/full_html/2009/11/aa10941-08/aa10941-08.html | last1=Moutou | first1=C. | last2=Mayor | first2=M. | last3=Lo Curto | first3=G. | last4=Udry | first4=S. | last5=Bouchy | first5=F. | last6=Benz | first6=W. | last7=Lovis | first7=C. | last8=Naef | first8=D. | last9=Pepe | first9=F. | last10=Queloz | first10=D. | last11=Santos | first11=N. C. | journal=Astronomy and Astrophysics | volume=496 | issue=2 | pages=513–19 | date=2009 | arxiv=0810.4662 | bibcode=2009A&A...496..513M | doi=10.1051/0004-6361:200810941 | s2cid=116707055 }}</ref>
* [[WASP-72]] is a star around 1.4 times as massive that has begun to cool and expand off the main sequence, reaching double the Sun's diameter. It has a planet around as massive as Jupiter orbiting it every 2.2 days.<ref>{{cite journal | title=WASP-64 b and WASP-72 b: two new transiting highly irradiated giant planets | vauthors=Gillon M, Anderson DR, Collier-Cameron A, Doyle AP, Fumel A, Hellier C, Jehin E, Lendl M, Maxted PF, Montalbán J, Pepe F, Pollacco D, Queloz D, Ségransan D, Smith AM, Smalley B, Southworth J, Triaud AH, Udry S, West RG | journal=Astronomy & Astrophysics |volume= 552| id=A82|pages= 13 |year=2013 | doi= 10.1051/0004-6361/201220561 |bibcode=2013A&A...552A..82G|arxiv = 1210.4257 | s2cid=53687206 }}</ref>
* [[WASP-72]] is a star around 1.4 times as massive that has begun to cool and expand off the main sequence, reaching double the Sun's diameter. It has a planet around as massive as Jupiter orbiting it every 2.2 days.<ref>{{cite journal | title=WASP-64 b and WASP-72 b: two new transiting highly irradiated giant planets | vauthors=Gillon M, Anderson DR, Collier-Cameron A, Doyle AP, Fumel A, Hellier C, Jehin E, Lendl M, Maxted PF, Montalbán J, Pepe F, Pollacco D, Queloz D, Ségransan D, Smith AM, Smalley B, Southworth J, Triaud AH, Udry S, West RG | journal=Astronomy & Astrophysics |volume= 552| id=A82|pages= 13 |year=2013 | doi= 10.1051/0004-6361/201220561 |bibcode=2013A&A...552A..82G|arxiv = 1210.4257 | s2cid=53687206 }}</ref>
* [[HD 20781]] and [[HD 20782]] are a pair of sunlike yellow main sequence stars that orbit each other. Each has been found to have planets.
* [[HD 20781]] and [[HD 20782]] are a pair of sunlike yellow main sequence stars that orbit each other. Each has been found to have planets.
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[[Helmi stream]] is a small galactic stream in Fornax. This small galaxy was destroyed by Milky Way 6 billion years ago. There was candidate for extragalactic planet, HIP 13044 b.
[[Helmi stream]] is a small galactic stream in Fornax. This small galaxy was destroyed by Milky Way 6 billion years ago. There was candidate for extragalactic planet, HIP 13044 b.

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[[File:The Hubble Ultra Deep Field seen with MUSE.jpg|thumb|left|The [[Hubble Ultra Deep Field]] seen with [[Multi-unit spectroscopic explorer|MUSE]].<ref>{{cite web|title=MUSE Probes Uncharted Depths of Hubble Ultra Deep Field – Deepest ever spectroscopic survey completed|url=https://www.eso.org/public/news/eso1738/|website=www.eso.org|access-date=30 November 2017}}</ref>]]


'''Outside'''
'''Outside'''


[[NGC 1097]] is a [[barred spiral galaxy]] in Fornax, about 45 million light-years from Earth. At magnitude 9, it is visible in medium amateur telescopes.{{sfn|Ridpath|Tirion|pp=148–149}} It is notable as a [[Seyfert galaxy]] with strong spectral emissions indicating ionized gases and a central [[supermassive black hole]].
[[NGC 1097]] is a [[barred spiral galaxy]] in Fornax, about 45 million light-years from Earth. At magnitude 9, it is visible in medium amateur telescopes.{{sfn|Ridpath|Tirion|2001|pp=148–149}} It is notable as a [[Seyfert galaxy]] with strong spectral emissions indicating ionized gases and a central [[supermassive black hole]].


'''Fornax Cluster'''
'''Fornax Cluster'''
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[[File:Galaxies in the Fornax Cluster.jpg|thumb|Galaxies in the Fornax Cluster]]


The '''[[Fornax Cluster]]''' is a [[galaxy cluster|cluster of galaxies]] lying at a distance of 19 mega[[parsec]]s (62 million [[light-year]]s).<ref name="Georgievetal2006">{{Cite journal | last1 = Jordán | first1 = A. | last2 = Blakeslee | first2 = J. P. | last3 = Côté | first3 = P. | last4 = Ferrarese | first4 = L. | last5 = Infante | first5 = L. | last6 = Mei | first6 = S. | last7 = Merritt | first7 = D. | author7-link = David Merritt
The '''[[Fornax Cluster]]''' is a [[galaxy cluster|cluster of galaxies]] lying at a distance of 19 mega[[parsec]]s (62 million [[light-year]]s).<ref name="Georgievetal2006">{{Cite journal | last1 = Jordán | first1 = A. | last2 = Blakeslee | first2 = J. P. | last3 = Côté | first3 = P. | last4 = Ferrarese | first4 = L. | last5 = Infante | first5 = L. | last6 = Mei | first6 = S. | last7 = Merritt | first7 = D. | author7-link = David Merritt
| last8 = Peng | first8 = E. W. | last9 = Tonry | first9 = J. | last10 = West | first10 = Michael J. | date = June 2006 | journal =The Astrophysical Journal Supplement Series | volume = 452 | issue = 1 | pages = 141–153 | title = The ACS Fornax Cluster Survey. I. Introduction to the Survey and Data Reduction Procedures | bibcode = 2007ApJS..169..213J | doi = 10.1086/512778 |arxiv = astro-ph/0702320 | s2cid = 17845709 | display-authors = 8 }}</ref> It is the second richest galaxy cluster within 100 million light-years, after the considerably larger [[Virgo Cluster]], and may be associated with the nearby [[Eridanus Group]]. It lies primarily in the constellation Fornax, with its southern boundaries partially crossing into the constellation of Eridanus, and covers an area of sky about 6° across or about 28 sq degrees.<ref>{{cite journal |last1= Drinkwater |first1= Michael J. |last2= Gregg |first2= Michael J. |last3= Colless |first3= Matthew |date= 19 Feb 2011 |title= Substructure and Dynamics of the Fornax Cluster |journal= The Astrophysical Journal |volume= 548 |issue= 2 |pages= L139–L142 |url= https://iopscience.iop.org/article/10.1086/319113 |doi= 10.1086/319113|arxiv=astro-ph/0012415 |access-date= 11 Mar 2021|hdl= 1885/40020 |s2cid= 13456590 |hdl-access= free }}</ref> The Fornax cluster is a part of larger [[Fornax Wall]].<ref>{{cite book |last1=O'Meara |first1=Stephen James |title=Deep-Sky Companions: Southern Gems |date=2013 |publisher=[[Cambridge University Press]] |isbn=978-1-107-01501-2|page=107 |url=https://books.google.com/books?id=S5QIEKns33sC&pg=PA107}}</ref> Down are some famous objects in this cluster:
| last8 = Peng | first8 = E. W. | last9 = Tonry | first9 = J. | last10 = West | first10 = Michael J. | date = June 2006 | journal =The Astrophysical Journal Supplement Series | volume = 452 | issue = 1 | pages = 141–153 | title = The ACS Fornax Cluster Survey. I. Introduction to the Survey and Data Reduction Procedures | bibcode = 2007ApJS..169..213J | doi = 10.1086/512778 |arxiv = astro-ph/0702320 | s2cid = 17845709 | display-authors = 8 }}</ref> It is the second richest galaxy cluster within 100 million light-years, after the considerably larger [[Virgo Cluster]], and may be associated with the nearby [[Eridanus Group]]. It lies primarily in the constellation Fornax, with its southern boundaries partially crossing into the constellation of Eridanus, and covers an area of sky about 6° across or about 28 sq degrees.<ref>{{cite journal |last1= Drinkwater |first1= Michael J. |last2= Gregg |first2= Michael J. |last3= Colless |first3= Matthew |date= 19 Feb 2011 |title= Substructure and Dynamics of the Fornax Cluster |journal= The Astrophysical Journal |volume= 548 |issue= 2 |pages= L139–L142 |url= https://iopscience.iop.org/article/10.1086/319113 |doi= 10.1086/319113|arxiv=astro-ph/0012415 |access-date= 11 Mar 2021|hdl= 1885/40020 |s2cid= 13456590 |hdl-access= free }}</ref> The Fornax cluster is a part of larger [[Fornax Wall]].<ref>{{cite book |last1=O'Meara |first1=Stephen James |title=Deep-Sky Companions: Southern Gems |date=2013 |publisher=[[Cambridge University Press]] |isbn=978-1-107-01501-2|page=107 |url=https://books.google.com/books?id=S5QIEKns33sC&pg=PA107}}</ref> Down are some famous objects in this cluster:


[[NGC 1365]] is another [[barred spiral galaxy]] located at a distance of 56 million light-years from Earth. Like NGC 1097, it is also a [[Seyfert galaxy]]. Its bar is a center of [[star formation]] and shows extensions of the spiral arms' [[dust lane]]s. The bright nucleus indicates the presence of an [[active galactic nucleus]] – a galaxy with a [[supermassive black hole]] at the center, accreting matter from the bar.<ref name="objects"/> It is a 10th magnitude galaxy associated with the [[Fornax Cluster]].{{sfn|Ridpath|Tirion|pp=148–149}}
[[NGC 1365]] is another [[barred spiral galaxy]] located at a distance of 56 million light-years from Earth. Like NGC 1097, it is also a [[Seyfert galaxy]]. Its bar is a center of [[star formation]] and shows extensions of the spiral arms' [[dust lane]]s. The bright nucleus indicates the presence of an [[active galactic nucleus]] – a galaxy with a [[supermassive black hole]] at the center, accreting matter from the bar.<ref name="objects"/> It is a 10th magnitude galaxy associated with the [[Fornax Cluster]].{{sfn|Ridpath|Tirion|2001|pp=148–149}}


[[Fornax A]] is a [[radio galaxy]] with extensive radio lobes that corresponds to the optical galaxy [[NGC 1316]], a 9th-magnitude galaxy.{{sfn|Ridpath|Tirion|2001|pp=148–149}} One of the closer [[active galaxy|active galaxies]] to Earth at a distance of 62 million light-years, Fornax A appears in the [[optical spectrum]] as a large [[elliptical galaxy]] with [[dust lane]]s near its core. These dust lanes have caused astronomers to discern that it recently [[galaxy merger|merged]] with a small [[spiral galaxy]]. Because it has a high rate of [[type Ia supernova]]e, NGC 1316 has been used to determine the size of the universe. The [[astrophysical jet|jet]]s producing the radio lobes are not particularly powerful, giving the lobes a more diffuse, knotted structure due to interactions with the [[intergalactic medium]].<ref name="objects">{{cite book |title = 300 Astronomical Objects: A Visual Reference to the Universe |last1 = Wilkins |first1 = Jamie |last2 = Dunn |first2 = Robert |publisher = Firefly Books |location = Buffalo, New York |date = 2006 |isbn = 978-1-55407-175-3}}</ref> Associated with this [[peculiar galaxy]] is an entire cluster of galaxies.{{sfn|Ridpath|Tirion|2001|pp=148-149}}
[[Fornax A]] is a [[radio galaxy]] with extensive radio lobes that corresponds to the optical galaxy [[NGC 1316]], a 9th-magnitude galaxy.{{sfn|Ridpath|Tirion|2001|pp=148–149}} One of the closer [[active galaxy|active galaxies]] to Earth at a distance of 62 million light-years, Fornax A appears in the [[optical spectrum]] as a large [[elliptical galaxy]] with [[dust lane]]s near its core. These dust lanes have caused astronomers to discern that it recently [[galaxy merger|merged]] with a small [[spiral galaxy]]. Because it has a high rate of [[type Ia supernova]]e, NGC 1316 has been used to determine the size of the universe. The [[astrophysical jet|jet]]s producing the radio lobes are not particularly powerful, giving the lobes a more diffuse, knotted structure due to interactions with the [[intergalactic medium]].<ref name="objects">{{cite book |title = 300 Astronomical Objects: A Visual Reference to the Universe |last1 = Wilkins |first1 = Jamie |last2 = Dunn |first2 = Robert |publisher = Firefly Books |location = Buffalo, New York |date = 2006 |isbn = 978-1-55407-175-3}}</ref> Associated with this [[peculiar galaxy]] is an entire cluster of galaxies.{{sfn|Ridpath|Tirion|2001|pp=148-149}}
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'''Distant universe'''
'''Distant universe'''
⚫
[[File:The Hubble Ultra Deep Field seen with MUSE.jpg|thumb|The [[Hubble Ultra Deep Field]] seen with [[Multi-unit spectroscopic explorer|MUSE]].<ref>{{cite web|title=MUSE Probes Uncharted Depths of Hubble Ultra Deep Field – Deepest ever spectroscopic survey completed|url=https://www.eso.org/public/news/eso1738/|website=www.eso.org|access-date=30 November 2017}}</ref>]]
[[File:Hubble Ultra Deep Field Video near constellation Fornax.webm|thumb|A video introduce the [[Hubble Ultra Deep Field]] and its location near Fornax]]
[[File:Hubble Ultra Deep Field Video near constellation Fornax.webm|thumb|A video introduce the [[Hubble Ultra Deep Field]] and its location near Fornax]]


Fornax has been the target of investigations into the furthest reaches of the [[universe]]. The [[Hubble Ultra Deep Field]] is located within Fornax, and the [[Fornax Cluster]], a small [[cluster of galaxies]], lies primarily within Fornax. At a meeting of the [[Royal Astronomical Society]] in [[United Kingdom|Britain]], a team from [[University of Queensland]] described 40 unknown "dwarf" galaxies in this constellation; follow-up observations with the [[Hubble Space Telescope]] and the [[European Southern Observatory]]'s [[Very Large Telescope]] revealed that [[ultra compact dwarfs]] are much smaller than previously known dwarf galaxies, about {{convert|120|ly|pc}} across.<ref>{{cite journal | title=Weighing Ultracompact Dwarf Galaxies in the Fornax Cluster |author1=Hilker, Michael |author2=Baumgardt, Holger |author3=Infante, Leopoldo |author4=Drinkwater, Michael |author5=Evstigneeva, Ekaterina |author6=Gregg, Michael | url=http://www.eso.org/sci/publications/messenger/archive/no.129-sep07/messenger-no129-49-52.pdf |archive-url=https://web.archive.org/web/20110604174928/http://www.eso.org/sci/publications/messenger/archive/no.129-sep07/messenger-no129-49-52.pdf |archive-date=2011-06-04 |url-status=live | journal= The Messenger | issue=129 |date= September 2007|volume=129 |page=49 |bibcode=2007Msngr.129...49H }}</ref>
Fornax has been the target of investigations into the furthest reaches of the [[universe]]. The [[Hubble Ultra Deep Field]] is located within Fornax, and the [[Fornax Cluster]], a small [[cluster of galaxies]], lies primarily within Fornax. At a meeting of the [[Royal Astronomical Society]] in [[United Kingdom|Britain]], a team from [[University of Queensland]] described 40 unknown "dwarf" galaxies in this constellation; follow-up observations with the [[Hubble Space Telescope]] and the [[European Southern Observatory]]'s [[Very Large Telescope]] revealed that [[ultra compact dwarfs]] are much smaller than previously known dwarf galaxies, about {{convert|120|ly|pc}} across.<ref>{{cite journal | title=Weighing Ultracompact Dwarf Galaxies in the Fornax Cluster |author1=Hilker, Michael |author2=Baumgardt, Holger |author3=Infante, Leopoldo |author4=Drinkwater, Michael |author5=Evstigneeva, Ekaterina |author6=Gregg, Michael | url=http://www.eso.org/sci/publications/messenger/archive/no.129-sep07/messenger-no129-49-52.pdf |archive-url=https://web.archive.org/web/20110604174928/http://www.eso.org/sci/publications/messenger/archive/no.129-sep07/messenger-no129-49-52.pdf |archive-date=2011-06-04 |url-status=live | journal= The Messenger | issue=129 |date= September 2007|volume=129 |page=49 |bibcode=2007Msngr.129...49H }}</ref>
`
`
[[UDFj-39546284]] is a candidate protogalaxy located in Fornax,<ref name="Space-20121212">{{cite web |last=Wall |first=Mike |title=Ancient Galaxy May Be Most Distant Ever Seen |url=http://www.space.com/18879-hubble-most-distant-galaxy.html |date=December 12, 2012 |publisher=[[Space.com]] |access-date=December 12, 2012 |quote=13.75 [[Big Bang]] – 0.38 = 13.37 }}</ref><ref name="NASA-2011-01-26">NASA, [http://www.nasa.gov/mission_pages/hubble/science/farthest-galaxy.html "NASA's Hubble Finds Most Distant Galaxy Candidate Ever Seen in Universe"], 26 January 2011</ref><ref name="heic1103">{{cite web |date=26 January 2011 |title=Hubble finds a new contender for galaxy distance record |publisher=Space Telescope (heic1103 – Science Release) |url=http://www.spacetelescope.org/news/heic1103/ |access-date=2011-01-27}}</ref><ref name="STScI-2011-05">HubbleSite, [http://hubblesite.org/newscenter/archive/releases/2011/05/text/ "NASA's Hubble Finds Most Distant Galaxy Candidate Ever Seen in Universe"], STScI-2011-05, 26 January 2011</ref> although recent analyses have suggested it is likely to be a lower redshift source.<ref name="Brammer2013">{{cite journal | bibcode = 2013ApJ...765L...2B | title=A Tentative Detection of an Emission Line at 1.6 mum for the z ~ 12 Candidate UDFj-39546284 | journal=The Astrophysical Journal | volume=765 | issue=1 | page=L2 | year=2013 | doi=10.1088/2041-8205/765/1/l2|arxiv = 1301.0317 | last1 = Brammer | first1 = Gabriel B.| s2cid=119226564 }}</ref><ref name="Bouwens2013">{{cite journal | bibcode = 2013ApJ...765L..16B | title=Photometric Constraints on the Redshift of z ~ 10 Candidate UDFj-39546284 from Deeper WFC3/IR+ACS+IRAC Observations over the HUDF | journal=The Astrophysical Journal | volume=765 | issue=1 | page=L16 | year=2013 | doi=10.1088/2041-8205/765/1/l16|arxiv = 1211.3105 | last1 = Bouwens | first1 = R. J. | last2 = Oesch | first2 = P. A. | last3 = Illingworth | first3 = G. D. | last4 = Labbé | first4 = I. | last5 = van Dokkum | first5 = P. G. | last6 = Brammer | first6 = G. | last7 = Magee | first7 = D. | last8 = Spitler | first8 = L. R. | last9 = Franx | first9 = M. | last10 = Smit | first10 = R. | last11 = Trenti | first11 = M. | last12 = Gonzalez | first12 = V. | last13 = Carollo | first13 = C. M.| s2cid=118570916 }}</ref>
[[UDFj-39546284]] is a candidate protogalaxy located in Fornax,<ref name="Space-20121212">{{cite web |last=Wall |first=Mike |title=Ancient Galaxy May Be Most Distant Ever Seen |url=http://www.space.com/18879-hubble-most-distant-galaxy.html |date=December 12, 2012 |publisher=[[Space.com]] |access-date=December 12, 2012 |quote=13.75 [[Big Bang]] – 0.38 = 13.37 }}</ref><ref name="NASA-2011-01-26">NASA, [http://www.nasa.gov/mission_pages/hubble/science/farthest-galaxy.html "NASA's Hubble Finds Most Distant Galaxy Candidate Ever Seen in Universe"], 26 January 2011</ref><ref name="heic1103">{{cite web |date=26 January 2011 |title=Hubble finds a new contender for galaxy distance record |publisher=Space Telescope (heic1103 – Science Release) |url=http://www.spacetelescope.org/news/heic1103/ |access-date=2011-01-27}}</ref><ref name="STScI-2011-05">{{Cite web| publisher=HubbleSite| title=NASA's Hubble Finds Most Distant Galaxy Candidate Ever Seen in Universe| url=http://hubblesite.org/newscenter/archive/releases/2011/05/text/| accessdate=26 January 2011| language=| archiveurl=https://archive.today/20130415015002/http://hubblesite.org/newscenter/archive/releases/2011/05/text/| archivedate=15 April 2013}}</ref> although recent analyses have suggested it is likely to be a lower redshift source.<ref name="Brammer2013">{{cite journal | bibcode = 2013ApJ...765L...2B | title=A Tentative Detection of an Emission Line at 1.6 mum for the z ~ 12 Candidate UDFj-39546284 | journal=The Astrophysical Journal | volume=765 | issue=1 | page=L2 | year=2013 | doi=10.1088/2041-8205/765/1/l2|arxiv = 1301.0317 | last1 = Brammer | first1 = Gabriel B.| s2cid=119226564 }}</ref><ref name="Bouwens2013">{{cite journal | bibcode = 2013ApJ...765L..16B | title=Photometric Constraints on the Redshift of z ~ 10 Candidate UDFj-39546284 from Deeper WFC3/IR+ACS+IRAC Observations over the HUDF | journal=The Astrophysical Journal | volume=765 | issue=1 | page=L16 | year=2013 | doi=10.1088/2041-8205/765/1/l16|arxiv = 1211.3105 | last1 = Bouwens | first1 = R. J. | last2 = Oesch | first2 = P. A. | last3 = Illingworth | first3 = G. D. | last4 = Labbé | first4 = I. | last5 = van Dokkum | first5 = P. G. | last6 = Brammer | first6 = G. | last7 = Magee | first7 = D. | last8 = Spitler | first8 = L. R. | last9 = Franx | first9 = M. | last10 = Smit | first10 = R. | last11 = Trenti | first11 = M. | last12 = Gonzalez | first12 = V. | last13 = Carollo | first13 = C. M.| s2cid=118570916 }}</ref>


[[GRB 190114C]] was a notable [[gamma ray burst]] explosion from a galaxy 4.5 billion light years away near the [[Fornax (constellation)|Fornax constellation]],<ref name="EA-20191120">{{cite news |author=ESA/Hubble Information Centre |title=Hubble studies gamma-ray burst with the highest energy ever seen |url=https://www.eurekalert.org/pub_releases/2019-11/eic-hsg112019.php |date=20 November 2019 |work=[[EurekAlert!]] |access-date=20 November 2019 }}</ref><ref name="ES-20191124">{{cite news |last=Byrd |first=Deborah |title=Epic cosmic explosion detected via faster-than-light particles - Space-based observatories detected a violent explosion in a galaxy billions of light-years away. It became the brightest source of high-energy cosmic gamma rays seen so far. Specialized Earth-based telescopes detected it via faster-than-light particles cascading through Earth's atmosphere. |url=https://earthsky.org/space/jan-14-2019-gamma-ray-burst-brightest-so-far |date=24 November 2019 |work=[[Earth & Sky]] |access-date=24 November 2019 }}</ref><ref name="NAT-20191120a">{{cite journal |last=Zhang |first=Ben |title=Extreme emission seen from γ-ray bursts - Cosmic explosions called γ-ray bursts are the most energetic bursting events in the Universe. Observations of extremely high-energy emission from two γ-ray bursts provide a new way to study these gigantic explosions. |date=20 November 2019 |journal=[[Nature (journal)|Nature]] |volume=575 |issue=7783 |pages=448–449 |doi=10.1038/d41586-019-03503-6 |arxiv=1911.09862 |pmid=31748718 |doi-access=free }}</ref> that was initially detected in January 2019.<ref name="GSFC-20190114">{{cite news |last=Palmer |first=David |title=GRB 190114C: Swift detection of a very bright burst with a bright optical counterpart |url=https://gcn.gsfc.nasa.gov/gcn/gcn3/23688.gcn3 |date=14 January 2019 |work=[[Goddard Space Flight Center]] |access-date=20 November 2019 }}</ref><ref name="AT-20190115">{{cite news |last=Mirzoyan |first=Razmik |title=First time detection of a GRB at sub-TeV energies; MAGIC detects the GRB 190114C |url=http://www.astronomerstelegram.org/?read=12390 |date=15 January 2019 |work=[[The Astronomer's Telegram]] |access-date=20 November 2019 }}</ref> According to astronomers, "the brightest light ever seen from Earth [to date] ... [the] biggest explosion in the Universe since the [[Big Bang]]".<ref name="LAD-2091122">{{cite news |last=Wood |first=Tom |title=Scientists Detect Biggest Explosion In The Universe Since The Big Bang |url=https://www.ladbible.com/news/technology-scientists-detect-biggest-explosion-in-the-universe-since-the-big-bang-20191122 |date=22 November 2019 |work=[[LADbible]] |access-date=23 November 2019 }}</ref>
[[GRB 190114C]] was a notable [[gamma ray burst]] explosion from a galaxy 4.5 billion light years away near the [[Fornax (constellation)|Fornax constellation]],<ref name="EA-20191120">{{cite news |author=ESA/Hubble Information Centre |title=Hubble studies gamma-ray burst with the highest energy ever seen |url=https://www.eurekalert.org/pub_releases/2019-11/eic-hsg112019.php |date=20 November 2019 |work=[[EurekAlert!]] |access-date=20 November 2019 }}</ref><ref name="ES-20191124">{{cite news |last=Byrd |first=Deborah |title=Epic cosmic explosion detected via faster-than-light particles - Space-based observatories detected a violent explosion in a galaxy billions of light-years away. It became the brightest source of high-energy cosmic gamma rays seen so far. Specialized Earth-based telescopes detected it via faster-than-light particles cascading through Earth's atmosphere. |url=https://earthsky.org/space/jan-14-2019-gamma-ray-burst-brightest-so-far |date=24 November 2019 |work=[[Earth & Sky]] |access-date=24 November 2019 }}</ref><ref name="NAT-20191120a">{{cite journal |last=Zhang |first=Ben |title=Extreme emission seen from γ-ray bursts - Cosmic explosions called γ-ray bursts are the most energetic bursting events in the Universe. Observations of extremely high-energy emission from two γ-ray bursts provide a new way to study these gigantic explosions. |date=20 November 2019 |journal=[[Nature (journal)|Nature]] |volume=575 |issue=7783 |pages=448–449 |doi=10.1038/d41586-019-03503-6 |arxiv=1911.09862 |pmid=31748718 |doi-access=free }}</ref> that was initially detected in January 2019.<ref name="GSFC-20190114">{{cite news |last=Palmer |first=David |title=GRB 190114C: Swift detection of a very bright burst with a bright optical counterpart |url=https://gcn.gsfc.nasa.gov/gcn/gcn3/23688.gcn3 |date=14 January 2019 |work=[[Goddard Space Flight Center]] |access-date=20 November 2019 }}</ref><ref name="AT-20190115">{{cite news |last=Mirzoyan |first=Razmik |title=First time detection of a GRB at sub-TeV energies; MAGIC detects the GRB 190114C |url=http://www.astronomerstelegram.org/?read=12390 |date=15 January 2019 |work=[[The Astronomer's Telegram]] |access-date=20 November 2019 }}</ref> According to astronomers, "the brightest light ever seen from Earth [to date] ... [the] biggest explosion in the Universe since the [[Big Bang]]".<ref name="LAD-2091122">{{cite news |last=Wood |first=Tom |title=Scientists Detect Biggest Explosion In The Universe Since The Big Bang |url=https://www.ladbible.com/news/technology-scientists-detect-biggest-explosion-in-the-universe-since-the-big-bang-20191122 |date=22 November 2019 |work=[[LADbible]] |access-date=23 November 2019 }}</ref>


==Equivalents==
==Equivalents==
In [[Chinese astronomy]], the stars that correspond to Fornax are within the [[White Tiger (Chinese astronomy)|White Tiger of the West]] (西方白虎, ''Xī Fāng Bái Hǔ'').<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060710.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日]</ref>
In [[Chinese astronomy]], the stars that correspond to Fornax are within the [[White Tiger (Chinese astronomy)|White Tiger of the West]] (西方白虎, ''Xī Fāng Bái Hǔ'').<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060710.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日] {{Webarchive|url=https://web.archive.org/web/20110716123113/http://aeea.nmns.edu.tw/2006/0607/ap060710.html |date=2011-07-16 }}</ref>
== Gallery==
<gallery mode="packed">
File:Rings of Relativity.jpg|Rings of Relativity
⚫
File:Galaxies in the Fornax Cluster.jpg|Galaxies in the Fornax Cluster
</gallery>


==See also==
==See also==
Line 147: Line 144:


== External links ==
== External links ==
{{Commons|Fornax}}
{{Commons}}
* [http://www.allthesky.com/constellations/fornax/constell.html The Deep Photographic Guide to the Constellations: Fornax]
* [http://www.allthesky.com/constellations/fornax/constell.html The Deep Photographic Guide to the Constellations: Fornax]
* [http://www.starrynightphotos.com/constellations/fornax_phoenix.htm Starry Night Photography – Fornax Constellation]
* [http://www.starrynightphotos.com/constellations/fornax_phoenix.htm Starry Night Photography – Fornax Constellation]
* [http://astrojan.eu5.org/fornax.htm The clickable Fornax]
* [http://astrojan.nhely.hu/fornax.htm The clickable Fornax]


{{Stars of Fornax}}
{{Stars of Fornax}}
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{{DEFAULTSORT:Constellation, Fornax}}
{{DEFAULTSORT:Constellation, Fornax}}
[[Category:Fornax (constellation)| ]]
[[Category:Fornax| ]]
[[Category:Southern constellations]]
[[Category:Southern constellations]]
[[Category:Constellations listed by Lacaille]]
[[Category:Constellations listed by Lacaille]]

Latest revision as of 20:07, 24 August 2024

This article is about the constellation. For the Roman goddess, see Fornax (mythology).
Fornax
Constellation
Fornax
List of stars in Fornax
AbbreviationFor
GenitiveFornacis
Pronunciation/ˈfɔːrnæks/, genitive /fɔːrˈneɪsɪs/
Symbolismthe brazier
Right ascension3h
Declination−30°
QuadrantSQ1
Area398 sq. deg. (41st)
Main stars2
Bayer/Flamsteed
stars		27
Stars with planets6
Stars brighter than 3.00m0
Stars within 10.00 pc (32.62 ly)2
Brightest starα For (3.80m)
Messier objects0
Meteor showers0
Bordering
constellations		Cetus
Sculptor
Phoenix
Eridanus
Visible at latitudes between +50° and −90°.
Best visible at 21:00 (9 p.m.) during the month of December.

Fornax (/ˈfɔːrnæks/) is a constellation in the southern celestial hemisphere, partly ringed by the celestial river Eridanus. Its name is Latin for furnace. It was named by French astronomer Nicolas Louis de Lacaille in 1756. Fornax is one of the 88 modern constellations.

The three brightest stars—Alpha, Beta and Nu Fornacis—form a flattened triangle facing south. With an apparent magnitude of 3.91, Alpha Fornacis is the brightest star in Fornax. Six star systems have been found to have exoplanets. The Fornax Dwarf galaxy is a small faint satellite galaxy of the Milky Way. NGC 1316 is a relatively close radio galaxy.

The Hubble's Ultra-Deep Field is located within the Fornax constellation.[1]

It is the 41st largest constellation in the night-sky, occupying an area of 398 square degrees. It is located in the first quadrant of the southern hemisphere (SQ1) and can be seen at latitudes between +50° and -90° during the month of December.

History

[edit]
Fornax Chemica can be seen below Cetus in this card from Urania's Mirror (1825).

The French astronomer Nicolas Louis de Lacaille first described the constellation in French as le Fourneau Chymique (the Chemical Furnace) with an alembic and receiver in his early catalogue,[2] before abbreviating it to le Fourneau on his planisphere in 1752,[3][4] after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment.[a] Lacaille Latinised the name to Fornax Chimiae on his 1763 chart.[2]

Characteristics

[edit]

The constellation Eridanus borders Fornax to the east, north and south, while Cetus, Sculptor and Phoenix gird it to the north, west and south respectively. Covering 397.5 square degrees and 0.964% of the night sky, it ranks 41st of the 88 constellations in size,[5] The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "For".[6] The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 8 segments (illustrated in infobox). In the equatorial coordinate system, the right ascension coordinates of these borders lie between 01h 45m 24.18s and 03h 50m 21.34s, while the declination coordinates are between −23.76° and −39.58°.[7] The whole constellation is visible to observers south of latitude 50°N.[b]

Features

[edit]
The constellation Fornax as it can be seen by the naked eye.

Stars

[edit]
See also: List of stars in Fornax

Lacaille gave Bayer designations to 27 stars now named Alpha to Omega Fornacis, labelling two stars 3.5 degrees apart as Gamma, three stars Eta, two stars Iota, two Lambda and three Chi. Phi Fornacis was added by Gould, and Theta and Omicron were dropped by Gould and Baily respectively. Upsilon, too, was later found to be two stars and designated as such.[2] Overall, there are 59 stars within the constellation's borders brighter than or equal to apparent magnitude 6.5.[c][5] However, there are no stars brighter than the fourth magnitude.[9]

The three brightest stars form a flattish triangle, with Alpha (also called Dalim[10]) and Nu Fornacis marking its eastern and western points and Beta Fornacis marking the shallow southern apex.[11] Originally designated 12 Eridani by John Flamsteed, Alpha Fornacis was named by Lacaille as the brightest star in the new constellation.[2] It is a binary star that can be resolved by small amateur telescopes. With an apparent magnitude of 3.91, the primary is a yellow-white subgiant 1.21 times as massive as the Sun that has begun to cool and expand after exhausting its core hydrogen, having swollen to 1.9 times the Sun's radius. Of magnitude 6.5, the secondary star is 0.78 times as massive as the Sun. It has been identified as a blue straggler, and has either accumulated material from, or merged with, a third star in the past. It is a strong source of X-rays.[12] The pair is 46.4 ± 0.3 light-years distant from Earth.[13]

Beta Fornacis is a yellow-hued giant star of spectral type G8IIIb of magnitude 4.5 that has cooled and swelled to 11 times the Sun's diameter,[14] 178 ± 2 light-years from Earth.[15] It is a red clump giant, which means it has undergone helium flash and is currently generating energy through the fusion of helium at its core.[16]

Nu Fornacis is 370 ± 10 light-years distant from Earth.[13] It is a blue giant star of spectral type B9.5IIIspSi that is 3.65 ± 0.18 times as massive and around 245 times as luminous as the Sun, with 3.2 ± 0.4 times its diameter.[17] It varies in luminosity over a period of 1.89 days—the same as its rotational period. This is because of differences in abundances of metals in its atmosphere; it belongs to a class of star known as an Alpha2 Canum Venaticorum variable.[18][19]

Shining with an apparent magnitude of 5.89, Epsilon Fornacis is a binary star system located 104.4 ± 0.3 light-years distant from Earth.[20] Its component stars orbit each other every 37 years. The primary star is around 12 billion years old and has cooled and expanded to 2.53 times the diameter of the Sun, while having only 91% of its mass. [21] Omega Fornacis is a binary star system composed of a blue main-sequence star of spectral type B9.5V and magnitude 4.96, and a white main sequence star of spectral type A7V and magnitude 7.88. The system is 470 ± 10 light-years distant from Earth.[22]

Kappa Fornacis is a triple star system composed of a yellow giant and a pair of red dwarfs.

R Fornacis is a long-period variable and carbon star.

LP 944-20 is a brown dwarf of spectral type M9 that has around 7% the mass of the Sun. Approximately 21 light-years distant from Earth, it is a faint object with an apparent magnitude of 18.69.[23] Observations published in 2007 showed that the atmosphere of LP 944-20 contains much lithium and that it has dusty clouds.[24] Smaller and less luminous still is 2MASS 0243-2453, a T-type brown dwarf of spectral type T6. With a surface temperature of 1040–1100 K, it has 2.4–4.1% the mass of the Sun, a diameter 9.2 to 10.6% of that of the Sun, and an age of 0.4–1.7 billion years.[25]

Six star systems in Fornax have been found to have planets:

  • Lambda2 Fornacis is a star about 1.2 times as massive as the Sun with a planet about as massive as Neptune, discovered by doppler spectroscopy in 2009. The planet has an orbit of around 17.24 days.[26]
  • HD 20868 is an orange dwarf with a mass around 78% that of the Sun, 151 ± 10 light-years away from Earth. It was found to have an orbiting planet approximately double the mass of Jupiter with a period of 380 days.[27]
  • WASP-72 is a star around 1.4 times as massive that has begun to cool and expand off the main sequence, reaching double the Sun's diameter. It has a planet around as massive as Jupiter orbiting it every 2.2 days.[28]
  • HD 20781 and HD 20782 are a pair of sunlike yellow main sequence stars that orbit each other. Each has been found to have planets.
  • HR 858 is a near naked eye visible star in Fornax, 31.3 parsecs away. In May 2019, it was announced to have at least 3 exoplanets as observed by transit method of the Transiting Exoplanet Survey Satellite.

Deep-sky objects

[edit]
Four globular clusters in Fornax.[29]

Local Group

NGC 1049 is a globular cluster 500,000 light-years from Earth. It is in the Fornax Dwarf Galaxy.[30] NGC 1360 is a planetary nebula in Fornax with a magnitude of approximately 9.0, 1,280 light-years from Earth. Its central star is of magnitude 11.4, an unusually bright specimen. It is five times the size of the famed Ring Nebula in Lyra at 6.5 arcminutes. Unlike the Ring Nebula, NGC 1360 is clearly elliptical.[31]

The Fornax Dwarf galaxy is a dwarf galaxy that is part of the Local Group of galaxies. It is not visible in amateur telescopes, despite its relatively small distance of 500,000 light-years.[32]

Helmi stream is a small galactic stream in Fornax. This small galaxy was destroyed by Milky Way 6 billion years ago. There was candidate for extragalactic planet, HIP 13044 b.

Outside

NGC 1097 is a barred spiral galaxy in Fornax, about 45 million light-years from Earth. At magnitude 9, it is visible in medium amateur telescopes.[32] It is notable as a Seyfert galaxy with strong spectral emissions indicating ionized gases and a central supermassive black hole.

Fornax Cluster

Galaxies in the Fornax Cluster

The Fornax Cluster is a cluster of galaxies lying at a distance of 19 megaparsecs (62 million light-years).[33] It is the second richest galaxy cluster within 100 million light-years, after the considerably larger Virgo Cluster, and may be associated with the nearby Eridanus Group. It lies primarily in the constellation Fornax, with its southern boundaries partially crossing into the constellation of Eridanus, and covers an area of sky about 6° across or about 28 sq degrees.[34] The Fornax cluster is a part of larger Fornax Wall.[35] Down are some famous objects in this cluster:

NGC 1365 is another barred spiral galaxy located at a distance of 56 million light-years from Earth. Like NGC 1097, it is also a Seyfert galaxy. Its bar is a center of star formation and shows extensions of the spiral arms' dust lanes. The bright nucleus indicates the presence of an active galactic nucleus – a galaxy with a supermassive black hole at the center, accreting matter from the bar.[36] It is a 10th magnitude galaxy associated with the Fornax Cluster.[32]

Fornax A is a radio galaxy with extensive radio lobes that corresponds to the optical galaxy NGC 1316, a 9th-magnitude galaxy.[32] One of the closer active galaxies to Earth at a distance of 62 million light-years, Fornax A appears in the optical spectrum as a large elliptical galaxy with dust lanes near its core. These dust lanes have caused astronomers to discern that it recently merged with a small spiral galaxy. Because it has a high rate of type Ia supernovae, NGC 1316 has been used to determine the size of the universe. The jets producing the radio lobes are not particularly powerful, giving the lobes a more diffuse, knotted structure due to interactions with the intergalactic medium.[36] Associated with this peculiar galaxy is an entire cluster of galaxies.[32]

NGC 1399 is a large elliptical galaxy in the Southern constellation Fornax, the central galaxy in the Fornax cluster. [37] The galaxy is 66 million light-years away from Earth. With a diameter of 130 000 light-years, it is one of the largest galaxies in the Fornax cluster and slightly larger than Milky Way. William Herschel discovered this galaxy on October 22, 1835.

NGC 1386 is a spiral galaxy located in the constellation Eridanus. It is located at a distance of circa 53 million light years from Earth and has apparent dimensions of 3.89' x 1.349'.[38] It is a Seyfert galaxy, the only one in Fornax Cluster.

NGC 1427A is an irregular galaxy in the constellation Eridanus. Its distance modulus has been estimated using the globular cluster luminosity function to be 31.01 ± 0.21 which is about 52 Mly.[33] It is the brightest dwarf irregular member of the Fornax cluster and is in the foreground of the cluster's central galaxy NGC 1399.[33]

NGC 1460 is a barred lenticular galaxy in the constellation Eridanus. It was discovered by John Herschel on November 28, 1837.[39] It is moving away from the Milky Way 1341 km/s. NGC 1460 has a Hubble classification of SB0, which indicates it is a barred lenticular galaxy. But, this one contains a huge bar at its core. The bar is spreading from center to the edge of the galaxy, as seen on Hubble image in the box. This bar is one of the largest seen in barred lenticular galaxies.

There are also first ultracompact dwarf galaxies discovered.

Distant universe

The Hubble Ultra Deep Field seen with MUSE.[40]
A video introduce the Hubble Ultra Deep Field and its location near Fornax

Fornax has been the target of investigations into the furthest reaches of the universe. The Hubble Ultra Deep Field is located within Fornax, and the Fornax Cluster, a small cluster of galaxies, lies primarily within Fornax. At a meeting of the Royal Astronomical Society in Britain, a team from University of Queensland described 40 unknown "dwarf" galaxies in this constellation; follow-up observations with the Hubble Space Telescope and the European Southern Observatory's Very Large Telescope revealed that ultra compact dwarfs are much smaller than previously known dwarf galaxies, about 120 light-years (37 pc) across.[41] ` UDFj-39546284 is a candidate protogalaxy located in Fornax,[42][43][44][45] although recent analyses have suggested it is likely to be a lower redshift source.[46][47]

GRB 190114C was a notable gamma ray burst explosion from a galaxy 4.5 billion light years away near the Fornax constellation,[48][49][50] that was initially detected in January 2019.[51][52] According to astronomers, "the brightest light ever seen from Earth [to date] ... [the] biggest explosion in the Universe since the Big Bang".[53]

Equivalents

[edit]

In Chinese astronomy, the stars that correspond to Fornax are within the White Tiger of the West (西方白虎, Xī Fāng Bái Hǔ).[54]

See also

[edit]

Notes

[edit]
  1. ^ The exception is Mensa, named for the Table Mountain. The other thirteen (alongside Fornax) are Antlia, Caelum, Circinus, Horologium, Microscopium, Norma, Octans, Pictor, Pyxis, Reticulum, Sculptor and Telescopium.[2]
  2. ^ While parts of the constellation technically rise above the horizon to observers between 50°N and 66°N, stars within a few degrees of the horizon for to all intents and purposes unobservable.[5]
  3. ^ Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies.[8]

References

[edit]
  1. ^ "Hubble Ultra Deep Field". hubblesite.org. Retrieved February 2, 2024.
  2. ^ a b c d e Wagman, Morton (2003). Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others. Blacksburg, Virginia: The McDonald & Woodward Publishing Company. pp. 6–7, 152. ISBN 978-0-939923-78-6.
  3. ^ Ridpath, Ian. "Lacaille's Southern Planisphere of 1756". Star Tales. Self-published. Retrieved 7 November 2016.
  4. ^ Lacaille, Nicolas Louis (1756). "Relation abrégée du Voyage fait par ordre du Roi au cap de Bonne-espérance". Mémoires de l'Académie Royale des Sciences (in French): 519–592 [588].
  5. ^ a b c Ridpath, Ian. "Constellations: Andromeda–Indus". Star Tales. Self-published. Retrieved 7 November 2016.
  6. ^ Russell, Henry Norris (1922). "The New International Symbols for the Constellations". Popular Astronomy. 30: 469. Bibcode:1922PA.....30..469R.
  7. ^ "Fornax, Constellation Boundary". The Constellations. International Astronomical Union. Retrieved 7 November 2016.
  8. ^ Bortle, John E. (February 2001). "The Bortle Dark-Sky Scale". Sky & Telescope. Sky Publishing Corporation. Archived from the original on 31 March 2014. Retrieved 7 November 2016.
  9. ^ Ridpath, Ian. "Fornax". Star Tales. Self-published. Retrieved 7 November 2016.
  10. ^ "Naming Stars". IAU.org. Retrieved 30 July 2018.
  11. ^ Thompson, Mark (2013). A Down to Earth Guide to the Cosmos. Random House. p. 132. ISBN 978-1-4481-2691-0.
  12. ^ Fuhrmann, K.; Chini, R. (2015). "Multiplicity among F-type Stars. II". The Astrophysical Journal. 809 (1): 19. Bibcode:2015ApJ...809..107F. doi:10.1088/0004-637X/809/1/107. 107.
  13. ^ a b van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics. 474 (2): 653–64. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  14. ^ Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics". Astronomy & Astrophysics. 367 (2): 521–24. arXiv:astro-ph/0012289. Bibcode:2001A&A...367..521P. doi:10.1051/0004-6361:20000451. S2CID 425754.
  15. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  16. ^ Kubiak, M.; McWilliam, A.; Udalski, A.; Gorski, K. (2002). "Metal Abundance of Red Clump Stars in Baade's Window". Acta Astronomica. 52: 159–75. Bibcode:2002AcA....52..159K.
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