Editing Fornax (section)

===Stars===
{{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.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>

[[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,<ref name=cadars>{{cite journal|author=Pasinetti Fracassini, L. E.|author2=Pastori, L.|author3=Covino, S.|author4=Pozzi, A.|date=2001|title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics|journal=Astronomy & Astrophysics|volume=367|issue=2|pages=521–24|bibcode=2001A&A...367..521P|doi=10.1051/0004-6361:20000451|arxiv = astro-ph/0012289 |s2cid=425754}}</ref> 178 ± 2 light-years from Earth.<ref name=GaiaDR2beta>{{cite DR2|5064312731759992960}}</ref>  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.<ref name=Kubiak2002>{{cite journal | title=Metal Abundance of Red Clump Stars in Baade's Window | last1=Kubiak | first1=M. | last2=McWilliam | first2=A. | last3=Udalski | first3=A. | last4=Gorski | first4=K. | journal=Acta Astronomica | volume=52 | pages=159–75 | date=2002 | bibcode=2002AcA....52..159K}}</ref>

[[Nu Fornacis]] is 370 ± 10 light-years distant from Earth.<ref name="vanLeeuwen2007"/> 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.<ref name=aaa334_181>{{cite journal | last1=North | first1=P. | title=Do SI stars undergo any rotational braking? | journal=Astronomy and Astrophysics | volume=334 | pages=181–87 |date=1998 | bibcode=1998A&A...334..181N |arxiv = astro-ph/9802286 }}</ref> 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|Alpha<sup>2</sup> Canum Venaticorum variable]].<ref name="Leone 2000">{{cite journal | last1=Leone | first1=F. | last2=Catanzaro | first2=G. | last3=Malaroda | first3=S. | title=A spectroscopic study of the magnetic chemically peculiar star nu Fornacis | journal=Astronomy and Astrophysics | volume=359 | pages=635–638 | date=2000 | bibcode=2000A&A...359..635L }}</ref><ref name=gcvs>{{cite journal | last1=Samus | first1=N. N. | last2=Durlevich | first2=O. V.
| title=General Catalogue of Variable Stars | journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S | volume=1 | year=2009 | bibcode=2009yCat....102025S }}</ref>

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.<ref name=GaiaDR2eps>{{cite DR2|5071514326764428544}}</ref> 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.
<ref name=Jofre2015>{{cite journal | last1=Jofré | first1=E. | last2=Petrucci | first2=R. | last3=Saffe | first3=C. | last4=Saker | first4=L. | last5=Artur de la Villarmois | first5=E. | last6=Chavero | first6=C. | last7=Gómez | first7=M. | last8=Mauas | first8=P. J. D. | title=Stellar parameters and chemical abundances of 223 evolved stars with and without planets | journal=Astronomy & Astrophysics | display-authors=1 | volume=574 | pages=A50 | year=2015 | arxiv=1410.6422 | bibcode=2015A&A...574A..50J | doi=10.1051/0004-6361/201424474 | s2cid=53666931 }}</ref> [[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.<ref name=GaiaDR2omega>{{cite DR2|5069213731825915648}}</ref>

[[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.<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:
* [[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 | 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>
* [[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.