View source for Canopus

{{short description|Brightest star in the constellation of Carina}}
{{Other uses}}
{{Starbox begin
 | name=Canopus
}}
{{Starbox image
 | image=[[File:Canopus.jpg|255px]]
 | caption=An image of Canopus by [[Expedition 6]]
}}
{{Starbox observe
 | epoch=J2000
 | constell=[[Carina (constellation)|Carina]]
 | pronounce={{IPAc-en|k|ə|ˈ|n|oʊ|p|ə|s}}<ref>{{OED|Canopus}}</ref>
 | ra={{RA|06|23|57.10988}}<ref name="van Leeuwen2007">{{cite journal | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 }} [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ53e6b48255b3&-out.add=.&-source=I/311/hip2&recno=30362 Vizier catalog entry ]</ref>
 | dec={{DEC|-52|41|44.3810}}<ref name="van Leeuwen2007"/>
 | appmag_v=−0.74<ref name="Ducati 2002">{{cite journal | title=Catalogue of Stellar Photometry in Johnson's 11-color system | last1=Ducati | first1=J. R. | journal=CDS/ADC Collection of Electronic Catalogues | volume=2237 | pages=0 | date=2002 | bibcode=2002yCat.2237....0D }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ53e6b360304a&-out.add=.&-source=II/237/colors&recno=1155 Vizier catalog entry ]</ref>
}}
{{Starbox character
 | type=[[Blue loop]]
 | class=A9&nbsp;II<ref name=perkins>{{cite journal |bibcode=1989ApJS...69..301G |title=The early F-type stars – Refined classification, confrontation with Stromgren photometry, and the effects of rotation |journal=Astrophysical Journal Supplement Series |volume=69 |pages=301 |last1=Gray |first1=R. O. |last2=Garrison |first2=R. F. |year=1989 |doi=10.1086/191315}}</ref><ref>{{cite journal |bibcode=1993ASPC...45...59L |title=A Spectroscopic Study of High Galactic Latitude F Supergiant Stars |journal=Luminous High-Latitude Stars. The International Workshop on Luminous High-Latitude Stars |volume=45 |pages=59 |last1=Lopez-Cruz |first1=O. |last2=Garrison |first2=R. F. |year=1993}}</ref>
 | b-v=+0.15<ref name="Ducati 2002"/>
 | u-b=+0.10<ref name="Ducati 2002"/>
 | variable=
}}
{{Starbox astrometry
 | radial_v={{val|20.3|0.5}}<ref name="Gontcharov 2007">{{cite journal | title=Pullkovo Compilation of Radial Velocities for 39495 Hipparcos stars in a common system | last1=Gontcharov | first1=G. A. | journal=Astronomy Letters | volume=32 | issue=1 | pages=759–771 | date=2007 | bibcode=2006AstL...32..759G | doi=10.1134/S1063773706110065|arxiv = 1606.08053 | s2cid=119231169 }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ53e6b5f60fbd&-out.add=.&-source=III/252/table8&recno=9232 Vizier catalog entry ]</ref>
 | prop_mo_ra=19.93<ref name="van Leeuwen2007"/>
 | prop_mo_dec=23.24<ref name="van Leeuwen2007"/>
 | parallax=10.55
 | p_error=0.56
 | parallax_footnote=<ref name="van Leeuwen2007"/>
 | absmag_v=−5.71<ref name=smiljanic2006/>
|arxiv = 1606.08053 }}
{{Starbox detail
 | metal_fe=−0.07<ref name=smiljanic2006/>
 | mass=9.26–{{val|9.81|1.83}}<ref name=DomicianoDeSouza/>
 | radius=
{{val|73.3|5.2}}<ref name=DomicianoDeSouza>{{cite journal |doi=10.1051/0004-6361/202140478 |title=Refined fundamental parameters of Canopus from combined near-IR interferometry and spectral energy distribution |year=2021 |last1=Domiciano De Souza |first1=A. |last2=Zorec |first2=J. |last3=Millour |first3=F. |last4=Le Bouquin |first4=J.-B. |last5=Spang |first5=A. |last6=Vakili |first6=F. |journal=Astronomy & Astrophysics |volume=654 |pages=A19 |arxiv=2109.07153 |bibcode=2021A&A...654A..19D |s2cid=237513623}}</ref>
 | gravity={{Val|1.70|0.05}}<ref name=DomicianoDeSouza/>
 | rotational_velocity=9<ref name=ayres2018/>
 | rotation={{val|298|u=days|p=≥}}<ref name=Testa2004/>
 | luminosity={{val|16600|700|680|fmt=commas}}<ref name=DomicianoDeSouza/>
 | temperature=7,400<ref name=ayres2018>{{cite journal |bibcode=2018ApJ...854...95A |title=Cracking the Conundrum of F-supergiant Coronae |last1=Ayres |first1=Thomas R. |journal=The Astrophysical Journal |year=2018 |volume=854 |issue=2 |page=95 |doi=10.3847/1538-4357/aaa6d7 |arxiv=1802.02552 |s2cid=119101035 |doi-access=free }}</ref>
 | age_myr = 33–34<ref name=DomicianoDeSouza/>
}}
{{Starbox catalog
 | names={{odlist | name=Suhayl | name2=Suhel | name3=Suhail | B=α Carinae | CPD=−52°1941 | FK5=245 | HD=45348 | HIP=30438 | HR=2326 | SAO=234480| GC=8302 }}<ref name=SIMBAD>{{cite simbad | title=alf Car | access-date=2019-03-09 }}</ref>
}}
{{Starbox reference
 | Simbad=canopus
}}
{{Starbox end}}

'''Canopus''' is the brightest star in the southern [[constellation]] of [[Carina (constellation)|Carina]] and the [[list of brightest stars|second-brightest star]] in the [[night sky]]. It is also [[Bayer designation|designated]] '''α&nbsp;Carinae''', which is [[Romanization|romanized]] ([[Transliteration|transliterated]]) to '''Alpha&nbsp;Carinae'''. With a [[visual apparent magnitude]] of −0.74, it is outshone only by [[Sirius]].

Located around {{val|310|ul=light-years}} from the [[Sun]], Canopus is a [[bright giant]] of [[spectral type A9]], so it is essentially white when seen with the naked eye. It has a luminosity over 10,000 times the [[luminosity of the Sun]], is nine to ten times as [[mass of the Sun|massive]], and has expanded to 71 times the [[Sun's radius]].  Its enlarged [[photosphere]] has an [[effective temperature]] of around {{val|7400|u=K}}.  Canopus is undergoing [[stellar core|core]] [[helium fusion|helium burning]] and is currently in the so-called [[blue loop]] phase of its [[stellar evolution|evolution]], having already passed through the [[red-giant branch]] after exhausting the hydrogen in its core. Canopus is a [[X-ray astronomy|source of X-rays]], which are likely being emitted from its [[stellar corona|corona]].

The prominent appearance of Canopus means it has been the subject of mythological lore among many ancient peoples. Its proper name is generally considered to originate from the [[Greek mythology|mythological]] [[Canopus (mythology)|Canopus]], who was a navigator for [[Menelaus]], king of [[Sparta]]. The [[heliacal rising#Acronycal and cosmic(al)|acronycal rising]] marked the date of the Ptolemaia festival in Egypt. In ancient India, it was named [[Agastya]] after the revered [[Vedas|Vedic]] sage. For Chinese astronomers, it was known as the [[Old Man of the South Pole]]. In [[Islamic astronomy]], it is Suhail or Suhayl, a name that is also commonly used to imply rareness of appearance (as Canopus infrequently appeared to a gazer at Middle Eastern latitutes)

==Nomenclature==
The name ''Canopus'' is a Latinisation of the [[Ancient Greek]] name Κάνωβος/Kanôbos, recorded in Claudius Ptolemy's ''[[Almagest]]'' (c.150 AD). Eratosthenes used the same spelling.<ref name="ridpathCr"/> Hipparchos wrote it as Κάνωπος. [[John Flamsteed]] wrote Canobus,<ref>{{cite book|last=Flamsteed|first=John|title=Atlas coelestis|location=London, United Kingdom|date=1729|pages=Constellation Map of Southern Hemisphere|url=https://gallica.bnf.fr/ark:/12148/btv1b53096741t/f108.item.zoom}}</ref> as did [[Edmond Halley]] in his 1679 ''Catalogus Stellarum Australium''.<ref name="Halley 1679">{{cite book|last=Halley|first=Edmond|title=Catalogus stellarum australium; sive, Supplementum catalogi Tychenici, exhibens longitudines et latitudines stellarum fixarum, quae, prope polum Antarcticum sitae, in horizonte Uraniburgico Tychoni inconspicuae fuere, accurato calculo ex distantiis supputatas, & ad annum 1677 completum correctas...Accedit appendicula de rebus quibusdam astronomicis|publisher=T. James|location=London|date=1679|pages=30|url=http://babel.hathitrust.org/cgi/pt?id=mdp.39015007000170;view=1up;seq=41;size=150}}</ref> The name has two possible derivations, both listed in [[Richard Hinckley Allen]]'s seminal ''[[Star Names: Their Lore and Meaning]]''.

* The brightest star in the obsolete constellation of [[Argo Navis]], which represented the ship used by [[Jason]] and the [[Argonauts]], was given the name of a ship's pilot from another Greek legend: [[Canopus (mythology)|Canopus]], pilot of [[Menelaus]]' ship on his quest to retrieve [[Helen of Troy]] after she was taken by [[Paris (mythology)|Paris]].<ref name="hinkley63">{{cite book|first=Richard Hinckley|last=Allen|author-link=Richard Hinckley Allen|date=1963|orig-year=1899|title=Star Names: Their Lore and Meaning|pages=[https://archive.org/details/starnamestheirlo00alle/page/67 67–72]|edition=Revised|publisher=Dover Publications|location=New York | isbn=((0-486-21079-0)) | url-access=registration|url=https://archive.org/details/starnamestheirlo00alle/page/67}}</ref>
*  A ruined ancient Egyptian port named [[Canopus, Egypt|Canopus]] lies near the mouth of the [[Nile]], site of the [[Battle of the Nile]].  It is speculated that its name is derived from the Egyptian [[Coptic language|Coptic]] ''Kahi Nub'' ("Golden Earth"), which refers to how Canopus would have appeared near the horizon in [[ancient Egypt]], reddened by atmospheric extinction from that position.<ref name="hinkley63"/><ref name=lynn1905>{{cite journal |bibcode=1905Obs....28..289L |title=The brightest fixed star and its name |last1=Lynn |first1=W. T. |journal=The Observatory |year=1905 |volume=28 |page=289 }}</ref>

In 2016, the [[International Astronomical Union]] organized a [[IAU Working Group on Star Names|Working Group on Star Names]] (WGSN) to catalog and standardize proper names for stars.<ref name="WGSN">{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN) | website=iau.org | publisher=[[International Astronomical Union]] | access-date=22 May 2016}}</ref> The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included ''Canopus'' for this star.<ref name="WGSN1">{{cite web | url=https://www.iau.org/static/science/scientific_bodies/working_groups/280/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 | website=iau.org | publisher=International Astronomical Union | access-date=2020-09-06 }}</ref> Canopus is now included in the ''IAU Catalog of Star Names''.<ref name="IAU-CSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=IAU Catalog of Star Names | website=iau.org | publisher=International Astronomical Union | access-date=2020-09-06}}</ref>

Canopus traditionally marked the steering oar of the ship [[Argo Navis]].<ref>{{cite journal | title = On Frederick de Houtman's Catalogue of Southern Stars, and the Origin of the Southern Constellations | last1= Knobel|first1=E. B. |journal = [[Monthly Notices of the Royal Astronomical Society]] | volume= 77| issue= 5 | pages=414–432 [422] | bibcode = 1917MNRAS..77..414K |date=1917 | doi=10.1093/mnras/77.5.414| doi-access=free }}</ref><ref name="ridpathCr"/> German celestial cartographer [[Johann Bayer]] gave it—as the brightest star in the constellation—the [[Bayer designation|designation]] of ''α&nbsp;Argus'' ([[Latinisation of names|Latinised]] to ''Alpha Argus'') in 1603. In 1763, French astronomer [[Nicolas Louis de Lacaille]] divided the huge constellation into three smaller ones,<ref name=Glass2012>{{cite book | title=Nicolas-Louis De La Caille, Astronomer and Geodesist | first=Ian Stewart | last=Glass | date=November 17, 2012 | page=73 | isbn=9780191649608 | publisher=OUP Oxford | url=https://books.google.com/books?id=eZjlHAIBeRAC&pg=PT73 }}</ref> and hence Canopus became ''α&nbsp;Carinae'' ([[Latinisation of names|Latinised]] to ''Alpha Carinae''). It is listed in the [[Bright Star Catalogue]] as HR 2326, the [[Henry Draper Catalogue]] as HD 45348, and the [[Hipparcos catalogue]] as HIP 30438.<ref name=SIMBAD/> Flamsteed did not number this southern star, but [[Benjamin Apthorp Gould]] gave it the number 7 (7 G. Carinae) in his ''Uranometria Argentina''.<ref name=Gould1878>{{cite journal | title=Uranometria Argentina: Brightness and position of every fixed star, down to the seventh magnitude, within one hundred degrees of the South Pole; with atlas | last=Gould | first=Benjamin Apthorp | journal=Resultados del Observatorio Nacional Argentino | volume=1 | page=140 | date=1878 | bibcode=1879RNAO....1....1G }}</ref>

An occasional name seen in English is ''Soheil'', or the feminine Soheila; in Turkish is ''Süheyl'', or the feminine Süheyla, from the Arabic name for several bright stars, سهيل ''suhayl'',<ref name="hinkley63"/> and Canopus was known as Suhel {{IPAc-en|'|s|uː|h|E|l}} in medieval times.<ref name=kunitzsch/> Alternative spellings include Suhail, Souhail, Suhilon, Suheyl, Sohayl, Sohail, Suhayil, Shoel, Sohil, Soheil, Sahil, Suhayeel, Sohayil, Sihel, and Sihil.<ref name="hinkley63"/> An alternative name was ''Wazn'' "weight" or ''Haḍar'' "ground" , implying the anchor stone used by ship, rather than being related to its low position near the horizon.<ref name="hinkley63"/> Hence comes its name in the ''[[Alfonsine tables]]'', Suhel ponderosus, a Latinization of ''Al Suhayl al Wazn''.<ref name="hinkley63"/> Its Greek name was revived during the [[Renaissance]].<ref name=kunitzsch>{{cite book |last1=Kunitzsch|first1=Paul |last2=Smart|first2=Tim |date = 2006|title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |edition = 2nd rev. |publisher = Sky Publishing Corporation |location = Cambridge, Massachusetts |isbn = 978-1-931559-44-7 |page = 23}}</ref>

==Observation==
[[File:Carina constellation map.svg|thumb|left|The constellation [[Carina (constellation)|Carina]] with Canopus towards the right (west)]]
The Muslim astronomer [[Ibn Rushd]] went to [[Marrakesh]] (in Morocco) to observe the star in 1153, as it was invisible in his native [[Córdoba, Spain|Córdoba]], [[Al-Andalus]]. He used the different visibility in different latitudes to argue that the [[Spherical Earth|Earth is round]], following Aristotle's argument which held that such an observation was only possible if the Earth was a relatively small sphere.<ref name=ibn_rushd>{{cite encyclopedia|first1=Juan|last1=Vernet|author-link1=Juan Vernet|first2=Julio|last2=Samsó|author-link2=Julio Samsó |title=The development of Arabic science in Andalusia |page=264|editor=[[Roshdi Rashed]]|encyclopedia=Encyclopedia of the History of Arabic Science | date=1996|publisher=Routledge|isbn=978-0-415-12410-2|oclc=912501823}}</ref>

English explorer [[Robert Hues]] brought Canopus to the attention of European observers in his 1592 work ''Tractatus de Globis'', along with [[Achernar]] and [[Alpha Centauri]], noting:<blockquote>"Now, therefore, there are but three [[First-magnitude star|Stars of the first magnitude]] that I could perceive in all those parts which are never seene here in England. The first of these is that bright Star in the sterne of [[Argo Navis|Argo]] which they call Canobus. The second is in the end of [[Eridanus (constellation)|Eridanus]]. The third is in the right foote of the [[Centaurus|Centaure]]."<ref>Knobel, p. 416.</ref></blockquote>

[[File:Vela and Surrounding Constellations (ground-based image).jpg|right|thumb|Wide angle view showing Canopus and other prominent stars with the Milky Way|alt=A field of stars against the Milky Way background with the prominent stars and constellations labelled]]
In the [[Southern Hemisphere]], Canopus and [[Sirius]] are both visible high in the sky simultaneously, and reach a [[meridian (astronomy)|meridian]] just {{val|21|u=minutes}} apart. Brighter than [[first-magnitude star|first magnitude]], Canopus can be seen by naked eye in the early twilight. Mostly visible in mid to late summer in the Southern Hemisphere, Canopus [[Culmination|culminates]] at midnight on December 27,<ref name="motz" /> and at 9 PM on February 11.<ref name="Schaaf257">Schaaf, p. 257.</ref>

When seen from latitudes south of {{DEC|37|18}}&nbsp;S, Canopus is a [[circumpolar star]]. Since Canopus is so far south in the sky, it never rises in mid- to far-northern latitudes; in theory the northern limit of visibility is latitude {{DEC|37|18}} north. This is just south of [[Athens]], [[San Francisco]], and [[Seoul]], and very close to [[Seville]] and [[Agrigento]]. It is almost exactly the latitude of [[Lick Observatory]] on [[Mount Hamilton (California)|Mt. Hamilton, California]], from which it is readily visible because of the effects of elevation and [[atmospheric refraction]], which add another degree to its apparent altitude. Under ideal conditions, it can be spotted as far north as latitude {{DEC|37|31}} from the Pacific coast.<ref>D. Gieringer, "Exploring the Tropic of Canopus", ''Astronomy'', December 1985, p.24.</ref> Another northernmost record of visibility came from [[Mount Nemrut]] in Turkey, latitude {{DEC|37|59}}.<ref>{{cite web |last1=Tezel |first1=Tunç |author-link=Tunç Tezel |url=http://www.twanight.org/newTWAN/photos.asp?ID=3004572 |title=Zodiacal Light and Nemrut Heritage |work=The World At Night (TWAN) |access-date=17 March 2014 |date=8 Oct 2013 |archive-url=https://web.archive.org/web/20140317134955/http://www.twanight.org/newTWAN/photos.asp?ID=3004572 |archive-date=17 March 2014 |url-status=dead }}</ref> It is more easily visible in places such as the Gulf Coast and Florida, and the island of [[Crete]] (Greece) where the best season for viewing it around 9 p.m. is during late January and early February.<ref name="motz">{{cite book|last1=Motz|first1=Lloyd|last2=Nathanson|first2=Carol|title=The Constellations: An Enthusiast's Guide to the Night Sky|publisher=Aurum Press|location=London, United Kingdom|date=1991|pages=376–77|isbn=1-85410-088-2}}</ref>

Canopus has a B–V [[color index]] of +0.15—where 0 is a blue-white—indicating it is essentially white, although it has been described as yellow-white. Canopus' spectral type has been given as F0 and the incrementally warmer A9. It is less yellow than [[Altair]] or [[Procyon]], with indices measured as 0.22 and 0.42, respectively.<ref name=Hoffleit1991>{{cite book | title=Bright Star Catalogue | edition=5th Revised | last1=Hoffleit | first1=D. | last2=Warren Jr. | first2=W. H. | date=1991 | publisher=[[Centre de Données astronomiques de Strasbourg|CDS]] }}</ref> Some observers may have perceived Canopus as yellow-tinged because it is low in the sky and hence subject to atmospheric effects.<ref name="Schaaf112">Schaaf, pp. 112–13.</ref> [[Patrick Moore]] said that it never appeared anything but white to him.<ref name="moore2000">{{cite book | first1=Patrick | last1=Moore | title=Exploring the night sky with binoculars | edition=4th | publisher=Cambridge University Press | year=2000 | isbn=9780521793902 | page=[https://archive.org/details/exploringnightsk00moor/page/69 69] | url=https://archive.org/details/exploringnightsk00moor| url-access=registration }}</ref> The [[bolometric correction]] for Canopus is 0.00,<ref name=smiljanic2006/> indicating that the visual [[absolute magnitude]] and bolometric absolute magnitude are equal.

Canopus was previously proposed to be a member of the [[Scorpius–Centaurus association]], however it is not located near the subgroups of that association, and has not been included as a Sco-Cen member in kinematic studies that used [[Hipparcos]] astrometric data.<ref name="deZeeuw">{{cite journal|last1=de Zeeuw|first1=P.T. |last2=Hoogerwerf|first2=R. |last3=de Bruijne|first3=J.H.J |last4=Brown|first4=A.G.A |last5=Blaauw|first5=A. |date=1999|title=A HIPPARCOS Census of the Nearby OB Associations |journal=The Astronomical Journal |volume=117 |issue=1 |pages=354–399|bibcode=1999AJ....117..354D |doi=10.1086/300682|arxiv = astro-ph/9809227 |s2cid=16098861 }}</ref> Canopus is not thought to be a member of any nearby young stellar groups.<ref name=mamajek>{{cite AV media | url=https://figshare.com/articles/Canopus_B_A_Candidate_Common_Proper_Motion_Companion_to_the_Second_Brightest_Star/1132696 | title=Canopus B: A Candidate Common Proper Motion Companion to the Second Brightest Star | last=Mamajek | first=Eric | year=2014 | publisher=Figshare | doi=10.6084/m9.figshare.1132696.v3 | access-date=2020-09-10 }}</ref>  In 2014, astronomer Eric Mamajek reported that an extremely magnetically active M dwarf (having strong coronal X-ray emission), 1.16 degrees south of Canopus, appears to share a [[common proper motion]] with Canopus. The projected separation of the M dwarf 2MASS J06234738-5351131 ("Canopus B") is approximately 1.9 parsecs. However, despite this large separation, it is still within the estimated tidal radius (2.9 parsecs) for the massive star Canopus.<ref name="mamajek"/>

Since it is more luminous than any star closer to Earth, Canopus has been the brightest star in the night sky during three epochs over the past four million years. Other stars appear brighter only during relatively temporary periods, during which they are passing the Solar System much closer than Canopus. About 90,000 years ago, [[Sirius]] moved close enough that it became brighter than Canopus, and that will remain so for another 210,000 years. But in 480,000 years, as Sirius moves further away and appears fainter, Canopus will once again be the brightest, and will remain so for a period of about 510,000 years.<ref name="tomkin98">{{cite journal|last=Tomkin|first=Jocelyn|date=April 1998|title=Once and Future Celestial Kings|journal=Sky and Telescope|volume=95|issue=4|pages=59–63|bibcode=1998S&T....95d..59T}}</ref><!-- this all comes from same paper -->

===Role in navigation===
[[File:Constellation_Carina.jpg|thumb|right|upright|Canopus is the brightest star in the constellation of Carina (top).]]
The southeastern wall of the [[Kaaba]] in [[Mecca]] is aligned with the rising point of Canopus, and is also named ''Janūb''.<ref>{{cite book|author=George Nicholas Atiyeh|title=The Book in the Islamic World: The Written Word and Communication in the Middle East|url=https://books.google.com/books?id=t4LEfpCW_kQC|date=1 January 1995|publisher=SUNY Press|isbn=978-0-7914-2473-5}}</ref> The [[Negev Bedouin|Bedouin]] people of the [[Negev]] and [[Sinai Peninsula|Sinai]] knew Canopus as ''Suhayl'', and used it and [[Polaris]] as the two principal stars for navigation at night. Because it disappears below the horizon in those regions, it became associated with a changeable nature, as opposed to always-visible Polaris, which was circumpolar and hence 'steadfast'.<ref>{{cite journal |last=Bailey |first=Clinton |date=1974 |title=Bedouin Star-Lore in Sinai and the Negev |journal=Bulletin of the School of Oriental and African Studies, University of London |volume=37 |issue=3 |pages=580–96 |type=abstract |doi=10.1017/S0041977X00127491 |jstor=613801|s2cid=131527348 }}</ref>

The south [[celestial pole]] can be approximately located using Canopus and two different bright stars. The first, [[Achernar]], makes an [[equilateral triangle]] between the stars and the south pole. One can also locate the pole more roughly using an imaginary line between Sirius and Canopus; Canopus will be approximately at the midpoint, being {{DEC|36}} one way to Sirius and {{DEC|37}} to the pole.<ref>{{Cite book| last1 = Heifetz| first1 = Milton| last2 = Tirion| first2 = Wil| title = A Walk Through the Heavens: A Guide to Stars and Constellations and Their Legends | date = 2007| publisher = [[Cambridge University Press]]| location = Cambridge | page = 38 | isbn=978-1-139-46138-2}}</ref>

Canopus's brightness and location well off the [[ecliptic]] make it useful for space navigation. Many spacecraft carry a special camera known as a "Canopus [[star tracker|Star Tracker]]" plus a Sun sensor for [[Orientation (geometry)|attitude]] determination. [[Mariner 4]] used Canopus for [[Spin-stabilisation|second axis stabilisation]] (after locking on the Sun) in 1964, the first time a star had been used.<ref>{{cite book |last1=United States. National Aeronautics and Space Administration. Scientific and Technical Information Division |title=Astronautics and Aeronautics, 1964: Chronology on Science, Technology and Policy |date=1965 |publisher=Scientific and Technical Information Division, National Aeronautics and Space Administration |page=398 |url=https://books.google.com/books?id=ckkCAAAAIAAJ&pg=PA398}}</ref>

==Spectrum==
Canopus was little-studied by western scientists before the 20th century.  It was given a spectral class of F in 1897, an early use of this extension to [[Secchi class]] I, applied to those stars where the hydrogen lines are relatively weak and the [[calcium K line]] relatively strong.<ref>{{cite journal |bibcode=1897ApJ.....6..349P |title=Spectra of bright southern stars |last1=Pickering |first1=E. C. |last2=Cannon |first2=A. J. |journal=The Astrophysical Journal |year=1897 |volume=6 |page=349 |doi=10.1086/140407 |doi-access=free }}</ref>  It was given as a standard star of F0 in the [[Henry Draper Catalogue]], with the spectral type F0 described as having hydrogen lines half the strength of an A0 star and the calcium K line three times as strong as Hδ.<ref name=hd>{{cite journal |bibcode=1918AnHar..92....1C |title=The Henry Draper catalogue : 4h, 5h and 6h |last1=Cannon |first1=Annie Jump |last2=Pickering |first2=Edward Charles |journal=Annals of Harvard College Observatory |year=1918 |volume=92 |page=1 }}</ref> American astronomer [[Jesse L. Greenstein|Jesse Greenstein]] was interested in stellar spectra and used the newly built [[Otto Struve Telescope]] at [[McDonald Observatory]] to analyze the star's spectrum in detail.<ref>{{cite book |last1=Trimble |first1=Virginia | first2= Thomas R. |last2=Williams | first3= Katherine | last3=Bracher| first4= Richard | last4=Jarrell| first5=Jordan D.| last5= Marché| first6=F. Jamil | last6=Ragep |title=Biographical Encyclopedia of Astronomers |date=2007 |publisher=Springer Science & Business Media |location=New York, New York |isbn=978-0-387-30400-7 |page=438 |url=https://books.google.com/books?id=t-BF1CHkc50C&pg=PA438}}</ref> In a 1942 paper, he reported that the spectrum is dominated by strong broad hydrogen lines.  There are also [[absorption line]]s of carbon, nitrogen, oxygen, sulphur, iron, and many ionised metals.<ref name=greenstein1942>{{cite journal |bibcode=1942ApJ....95..161G |title=The Spectrum of α Carinae |last1=Greenstein |first1=Jesse L. |journal=The Astrophysical Journal |year=1942 |volume=95 |page=161 |doi=10.1086/144382 |doi-access=free }}</ref> It was studied in the [[ultraviolet]] by an early astronomical satellite, [[Gemini XI]] in 1966.  The UV spectra were considered to be consistent with an F0 [[Supergiant star|supergiant]] having a temperature of {{val|6,900|fmt=commas|u=K}}, the accepted parameters for Canopus at the time.<ref name=kondo1970>{{cite journal |bibcode=1970ApJ...159..927K |title=Ultraviolet Spectrophotometry of Canopus from Gemini XI |last1=Kondo |first1=Y. |last2=Henize |first2=K. G. |last3=Kotila |first3=C. L. |journal=The Astrophysical Journal |year=1970 |volume=159 |page=927 |doi=10.1086/150370 |doi-access=free }}</ref> New Zealand-based astronomers [[John Hearnshaw]] and Krishna Desikachary examined the spectrum in greater detail, publishing their results in 1982.<ref>{{cite journal |title=The spectrum of Canopus | last1= Hearnshaw | first1= J. B.| last2= Desikachary | first2= K. | journal= Monthly Notices of the Royal Astronomical Society |  volume= 198 | year= 1982 | issue= 2 | pages= 311–320 | doi= 10.1093/mnras/198.2.311 | bibcode=1982MNRAS.198..311H| doi-access= free }}</ref><ref>{{cite journal |title=The spectrum of Canopus II - Analysis and composition | last1= Hearnshaw | first1= J. B.| last2= Desikachary | first2= K. | journal= Monthly Notices of the Royal Astronomical Society |  volume= 201 | year= 1982 | issue= 3 | pages= 707–721 | doi= 10.1093/mnras/201.3.707 | bibcode=1982MNRAS.201..707D| doi-access= free }}</ref>

When [[luminosity class]]es were added to the MK spectral classification scheme, Canopus was assigned class Iab indicating an intermediate luminosity supergiant.  This was based on the relative strengths of certain spectral lines understood to be sensitive to the luminosity of a star.<ref name=devaucoleurs>{{cite journal|title=Spectral types and luminosities of B, A and F southern stars|author=de Vaucouleurs, A.|journal=Monthly Notices of the Royal Astronomical Society|volume=117|page=449|date=1957|issue=4|bibcode=1957MNRAS.117..449D|doi=10.1093/mnras/117.4.449|doi-access=free}}</ref> In the [[Bright Star Catalogue]] 5th edition it is given the spectral class F0II, the luminosity class indicating a [[bright giant]].<ref name=bsc>{{cite book |bibcode=1991bsc..book.....H |year=1991 |title=The Bright star catalogue |last1=Hoffleit |first1=Dorrit |last2=Jaschek |first2=Carlos }}</ref>  [[Balmer line]] profiles and oxygen line strengths indicate the size and luminosity of Canopus.<ref name=kovtyukh2012>{{cite journal |bibcode=2012MNRAS.423.3268K |title=Accurate luminosities from the oxygen λ7771-4 Å triplet and the fundamental parameters of F-G supergiants |last1=Kovtyukh |first1=V. V. |last2=Gorlova |first2=N. I. |last3=Belik |first3=S. I. |journal=Monthly Notices of the Royal Astronomical Society |year=2012 |volume=423 |issue=4 |page=3268 |doi=10.1111/j.1365-2966.2012.21117.x |doi-access=free |arxiv=1204.4115 |s2cid=118683158 }}</ref>

When the effects of stellar rotation speed on spectral lines are accounted for, the MK spectral class of Canopus is adjusted to A9II.<ref name=perkins/>  Its spectrum consists mostly of absorption lines on a visible [[continuous spectrum|continuum]], but some emission has been detected.  For example, the [[calcium K line]] has weak emission wings on each side of the strong central absorption line, first observed in 1966.  The emission line profiles are usually correlated with the luminosity of the star as described by the [[Wilson-Bappu effect]], but in the case of Canopus they indicate a luminosity much lower than that calculated by other methods.<ref name=warner1966>{{cite journal|title=CA II emission in the spectrum of Canopus|journal=The Observatory |volume=86 |pages=82|date=April 1966|last=Warner |first=B. |bibcode=1966Obs....86...82W }}</ref>  More detailed observations have shown that the emission line profiles are variable and may be due to [[plage (astronomy)|plage]] areas on the surface of the star.  Emission can also be found in other lines such as the h and k lines of ionised magnesium.<ref name=bappu1984>{{cite journal |bibcode=1984BASI...12..196B |title=CA II K emission in Canopus |last1=Bappu |first1=M. K. V. |last2=Mekkaden |first2=M. V. |last3=Rao |first3=N. K. |journal=Bulletin of the Astronomical Society of India |year=1984 |volume=12 |page=196 }}</ref>

==Distance==
Before the launch of the [[Hipparcos]] satellite telescope, distance estimates for Canopus varied widely, from 96 [[light-year]]s to 1200 light-years (or 30 to 370 parsecs). For example, an old distance estimate of 200 parsecs (652 light years) gave it a luminosity of {{solar luminosity|80,000}},<ref>{{cite web | url=https://archive.org/stream/Galaxy_v23n06_1965-08#page/n129/mode/2up | title=Galaxy v23n06 (1965 08) }}</ref> far higher than modern estimates.<ref name=vlti>{{cite journal|bibcode=2013MNRAS.434..437C|arxiv=1306.3288|title=Fundamental parameters of 16 late-type stars derived from their angular diameter measured with VLTI/AMBER|journal=Monthly Notices of the Royal Astronomical Society|volume=434|issue=1|pages=437–450|last1=Cruzalèbes|first1=P.|last2=Jorissen|first2=A.|last3=Rabbia|first3=Y.|last4=Sacuto|first4=S.|last5=Chiavassa|first5=A.|last6=Pasquato|first6=E.|last7=Plez|first7=B.|last8=Eriksson|first8=K.|last9=Spang|first9=A.|last10=Chesneau|first10=O.|year=2013|doi=10.1093/mnras/stt1037|doi-access=free |s2cid=49573767}}</ref> The closer distance was derived from parallax measurements of around {{val|33|ul=mas}}.<ref name=vandekamp1943>{{cite journal |title=Note on the Parallax of Canopus|journal=Popular Astronomy |volume=51 |date=1943 |page=172 |last=van de Kamp |first=Peter|bibcode=1943PA.....51..172V }}</ref>  The larger distance derives from the assumption of a very bright [[absolute magnitude]] for Canopus.<ref name=vanzyl>{{cite book|author=J.E. van Zyl|title=Unveiling the Universe: An Introduction to Astronomy|url=https://books.google.com/books?id=Cj7uBwAAQBAJ&pg=PA184|date=6 December 2012|publisher=Springer Science & Business Media|isbn=978-1-4471-1037-8|pages=184–}}</ref>

Hipparcos established Canopus as being {{val|310|u=light-years}} ({{val|95|ul=parsecs}}) from the [[Solar System]]; this is based on its 2007 [[parallax]] measurement of {{Val|10.43|0.53|ul=mas}}.<ref name="van Leeuwen2007"/>  At 95 parsecs, the [[interstellar extinction]] for Canopus is low at 0.26 magnitudes.<ref name=DomicianoDeSouza/>  Canopus is too bright to be included in the normal observation runs of the [[Gaia satellite]] and there is no published Gaia parallax for it.<ref name=dr2>{{cite DR2}}</ref>

At present the star is drifting further away from the Sun with a [[radial velocity]] of 20&nbsp;km/s. Some 3.1&nbsp;million years ago it made the closest approach to the Sun at a distance of about {{convert|52.87|pc|ly|0|adj=ri0|order=flip|abbr=on|lk=off}}. Canopus is orbiting the Milky Way with a heliocentric velocity of 24.5&nbsp;km/s and a low [[orbital eccentricity|eccentricity]] of 0.065.<ref name=Anderson2012>{{citation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | title=XHIP: An extended hipparcos compilation | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | arxiv=1108.4971 | doi=10.1134/S1063773712050015 | s2cid=119257644 | postscript=. }}</ref>

==Physical characteristics==
[[File:Canopus.png|thumb|240x240px|Artistical representation of Canopus. The white color is due to the star having a higher temperature than the [[Sun]].]]
The [[absorption line]]s in the spectrum of Canopus shift slightly with a period of {{val|6.9|u=days}}.  This was first detected in 1906 and the [[doppler effect|Doppler]] variations were interpreted as orbital motion.<ref name=curtis1907>{{cite journal |bibcode=1907PASP...19R.259C |title=The orbits of the spectroscopic binaries alpha Carinae, kappa Velorum, and alpha Pavonis |last1=Curtis |first1=H. D. |journal=Publications of the Astronomical Society of the Pacific |year=1907 |volume=19 |page=259 |doi=10.1086/121781 }}</ref>  An orbit was even calculated, but no such companion exists and the small radial velocity changes are due to movements in the atmosphere of the star.  The maximum observed [[radial velocities]] are only 0.7 to {{val|1.6|ul=km/s}}.  Canopus also has a magnetic field that varies with the same period, detected by the [[Zeeman splitting]] of its spectral lines.<ref name=weiss1986>{{cite journal |bibcode=1986A&A...160..243W | title=The magnetic field of Canopus | last=Weiss | first=W. W. | journal= Astronomy and Astrophysics |volume= 160|pages= 243–250 | year=1986}}</ref>  Canopus is bright at [[microwave]] wavelengths, one of the few F-class stars to be detected by radio.<ref name=gudel2002>{{cite journal |bibcode=2002ARA&A..40..217G |title=Stellar Radio Astronomy: Probing Stellar Atmospheres from Protostars to Giants |last1=Güdel |first1=Manuel |journal=Annual Review of Astronomy and Astrophysics |year=2002 |volume=40 |pages=217–261 |doi=10.1146/annurev.astro.40.060401.093806 |arxiv=astro-ph/0206436 |s2cid=53633983 }}</ref> The [[rotation period]] of the star is not accurately known, but may be over three hundred days.<ref name=Testa2004>{{cite journal | title=The Density of Coronal Plasma in Active Stellar Coronae | last1=Testa | first1=Paola | last2=Drake | first2=Jeremy J. | last3=Peres | first3=Giovanni | journal=The Astrophysical Journal | volume=617 | issue=1 | pages=508–530 | date=December 2004 | doi=10.1086/422355 | arxiv=astro-ph/0405019 | bibcode=2004ApJ...617..508T | s2cid=17532089 }}</ref> The [[projected rotational velocity]] has been measured at 9&nbsp;km/s.<ref name=ayres2018/>

An early [[Interferometry|interferometric]] measurement of its [[angular diameter]] in 1968 gave a [[Limb darkening|limb-darkened]] value of {{val|6.86|ul=mas}}, close to the accepted modern value.<ref>{{cite journal |bibcode=1968ARA&A...6...13B |title=Measurement of Stellar Diameters |last1=Brown |first1=R. Hanbury |journal=Annual Review of Astronomy and Astrophysics |year=1968 |volume=6 |page=13 |doi=10.1146/annurev.aa.06.090168.000305 }}</ref>  [[Very-long-baseline interferometry]] has been used to calculate Canopus' angular diameter at {{val|6.9|ul=mas}}. Combined with distance calculated from its Hipparcos parallax, this gives it a radius of 71 times [[Solar radius|that of the Sun]].<ref name=vlti/> If it were at the centre of the Solar System, it would extend 90% of the way to the orbit of [[Mercury (planet)|Mercury]].<ref name=Kalerstars>{{cite web|url=http://stars.astro.illinois.edu/sow/canopus.html|title=Canopus|last=Kaler|first=Jim|work=Stars|publisher=University of Illinois|access-date=8 July 2012|date=26 June 2009}}</ref> The radius and temperature relative to the Sun means that it is 10,700 times more luminous than the Sun, and its position in the [[H-R diagram]] relative to theoretical [[stellar evolution|evolutionary]] tracks means that it is {{Val|8.0|0.3}} times as massive as the Sun.<ref name=vlti/>  Measurements of its shape find a 1.1° departure from spherical symmetry.<ref name=cruzalebes2015>{{cite journal |bibcode=2015MNRAS.446.3277C |title=Departure from centrosymmetry of red giants and supergiants measured with VLTI/AMBER |last1=Cruzalèbes |first1=P. |last2=Jorissen |first2=A. |last3=Chiavassa |first3=A. |last4=Paladini |first4=C. |last5=Rabbia |first5=Y. |last6=Spang |first6=A. |journal=Monthly Notices of the Royal Astronomical Society |year=2015 |volume=446 |issue=4 |page=3277 |doi=10.1093/mnras/stu2382 |doi-access=free }}</ref>

Canopus is a source of [[X-ray astronomy|X-rays]], which are probably produced by its corona, magnetically heated to several million [[Kelvin]]. The temperature has likely been stimulated by fast rotation combined with strong convection percolating through the star's outer layers.<ref name=ness>{{cite journal|bibcode=2004A&A...427..667N|title=On the sizes of stellar X-ray coronae|journal=Astronomy and Astrophysics|volume=427|issue=2|pages=667–683|last1=Ness|first1=J.-U.|last2=Güdel|first2=M.|last3=Schmitt|first3=J. H. M. M.|last4=Audard|first4=M.|last5=Telleschi|first5=A.|year=2004|doi=10.1051/0004-6361:20040504|arxiv = astro-ph/0407231 |s2cid=11468731}}</ref>  The soft X-ray sub-coronal X-ray emission is much weaker than the hard X-ray coronal emission.  The same behaviour has been measured in other F-class supergiants such as [[α Persei]] and is now believed to be a normal property of such stars.<ref name=ayres2018/>

== Evolution ==
The spectrum of Canopus indicates that it spent some 30 million years of its existence as a blue-white main sequence star <!-- source suggests B2V but may be too exact --> of around 10 solar masses, before exhausting its core hydrogen and [[Stellar evolution|evolving]] away from the [[main sequence]].<ref>{{cite journal |last1=Peimbert |first1=M. |last2=Wallerstein | first2= G.| last3= Pilachowski | first3= C. A. |title=An upper limit for the deuterium abundance in Canopus |journal=Astronomy and Astrophysics |date=1981 |volume=104 |issue=1 |pages=72–74 | bibcode=1981A&A...104...72P}}</ref> The position of Canopus in the [[H–R diagram]] indicates that it is currently in the core-helium burning phase.<ref name=vlti/>  It is an intermediate mass star that has left the [[red-giant branch]] before its core became [[degenerate matter|degenerate]] and is now in a [[blue loop]].<ref name=desouza>{{Cite journal | last1 = Domiciano De Souza | first1 = A. | last2 = Bendjoya | first2 = P. | last3 = Vakili | first3 = F. | last4 = Millour | first4 = F. | last5 = Petrov | first5 = R. G. | title = Diameter and photospheric structures of Canopus from AMBER/VLTI interferometry | doi = 10.1051/0004-6361:200810450 | journal = Astronomy and Astrophysics | volume = 489 | issue = 2 | pages = L5–L8 | year = 2008 |bibcode = 2008A&A...489L...5D | url = https://hal.archives-ouvertes.fr/hal-00316994/document | doi-access = free }}</ref>  Models of stellar evolution in the blue loop phase show that the length of the blue loop is strongly affected by rotation and mixing effects inside the star.  It is difficult to determine whether a star is currently evolving towards hotter temperature or returning to cooler temperatures, since the evolutionary tracks for stars with different masses overlap during the blue loops.<ref name=smiljanic2006>{{cite journal |bibcode=2006A&A...449..655S |title=CNO in evolved intermediate mass stars |last1=Smiljanic |first1=R. |last2=Barbuy |first2=B. |last3=De Medeiros |first3=J. R. |last4=Maeder |first4=A. |journal=Astronomy and Astrophysics |year=2006 |volume=449 |issue=2 |page=655 |doi=10.1051/0004-6361:20054377 |arxiv=astro-ph/0511329 |s2cid=3711409 }}</ref>

Canopus lies on the warm side of the [[instability strip]] and does not pulsate like [[Cepheid variables]] of a similar luminosity.<ref name=ayres2011>{{cite journal |doi=10.1088/0004-637X/738/2/120 |title=The Curious Case of the Alpha Persei Corona: A Dwarf in Supergiant's Clothing? |year=2011 |last1=Ayres |first1=Thomas R. |journal=The Astrophysical Journal |volume=738 |issue=2 |page=120 |bibcode=2011ApJ...738..120A |doi-access=free }}</ref>  However its atmosphere does appear to be unstable, showing strong signs of convection.<ref name=smiljanic2006/>

Canopus may be massive enough to explode by an [[Type II supernova|iron-core collapse supernova]].

==Cultural significance ==
Canopus was known to the ancient Mesopotamians and represented the city of [[Eridu]] in the ''Three Stars Each'' [[Babylonian star catalogues]] and later [[MUL.APIN]] around 1100 BC.<ref>{{cite journal  | last = Rogers  | first = John H.  | date = 1998  | title = Origins of the Ancient Constellations: I. The Mesopotamian Traditions  | journal = Journal of the British Astronomical Association  | volume = 108  | issue = 1  | pages = 9–28 | bibcode = 1998JBAA..108....9R}}</ref> Canopus was called MUL.NUN<sup>KI</sup> by the Babylonians, which translates as "star of the city of Eridu". Eridu was the southernmost and one of the oldest Sumerian cities. From there is a good view to the south, so that about 6000 years ago due to the precession of the Earth's axis the first rising of the star Canopus in Mesopotamia could be observed only from there at the southern meridian at midnight.<ref>{{Cite journal |last1=Bautsch |first1=Markus  |author2-link=Friedhelm Pedde |last2=Pedde |first2=Friedhelm |title=Canopus, der "Stern der Stadt Eridu" |url=https://wfs.berlin/wp-content/uploads/2023/05/BROplanet-juni2023ff_www.pdf |journal=Dem Himmel Nahe |issue=17 |pages=8–9 |issn=2940-9330|language=de}}</ref>

Today, the star [[Sigma Sagittarii]] is known by the common name Nunki.<ref name=allen>{{citation | page=359 | first1=Richard Hinckley | last1=Allen | title=Star Names, their lore and meaning}}</ref>

Canopus was not visible to the mainland [[Ancient Greece|ancient Greeks]] and [[Roman Empire|Romans]]; it was, however, visible to the [[ancient Egypt]]ians.<ref name="Schaaf107">Schaaf, p. 107.</ref> Hence [[Aratus]] did not write of the star as it remained below the horizon, while [[Eratosthenes]] and [[Ptolemy]]—observing from [[Alexandria]]—did, calling it ''Kanōbos''.<ref name=ridpathCr>{{cite web| url=http://www.ianridpath.com/startales/carina.html | title=Carina |last1=Ridpath|first1=Ian|publisher=self-published |work=Star Tales | access-date= 17 June 2023}}</ref> An [[Egypt]]ian priestly poet in the time of [[Thutmose III]] mentions the star as ''Karbana,'' "the star which pours his light in a glance of fire, when he disperses the morning dew."<ref name="hinkley63" /> Under the [[Ptolemies]], the star was known as ''Ptolemaion'' ([[Ancient Greek|Greek]]: Πτολεμαῖον) and its [[acronychal rising]] marked the date of the Ptolemaia festival, which was held every four years, from 262 to 145 BC.<ref>[[Martianus Capella]] 7.838, {{cite journal | last1 = Hazzard | last2 = Fitzgerald | year = 1991 | title = The Regulation of the Ptolemeia | journal = Journal of the Royal Astronomical Society of Canada | volume = 85 | pages = 6–23 |bibcode = 1991JRASC..85....6H }}; Hazzard. 2000. ''Imagination of a Monarchy: Studies in Ptolemaic Propaganda'', 34–36.</ref>

The Greek astronomer [[Posidonius]] used observations of Canopus to calculate quite accurately the [[Posidonius#Earth's_circumference | Earth's circumference]], around 90 – 120 BC.

[[File:Statue of Averroes in Córdoba, Spain.jpg|thumb|upright|[[Averroes]], who used his 1153 observation of Canopus in [[Marrakesh]] while the star was invisible in his native Spain as an argument that the [[Spherical Earth|Earth is round]]<ref name=ibn_rushd/>]]

===India===
In Indian [[Vedas|Vedic literature]], Canopus is associated with the sage [[Agastya]], one of the ancient [[siddhar]]s and [[rishi]]s (the others are associated with the stars of the [[Big Dipper]]).<ref name="Frawley 1993">{{cite book|last=Frawley|first=David|title=Gods, Sages and Kings: Vedic Secrets of Ancient Civilization|publisher=Motilal Banarsidass |location=New Delhi, India|date=1993}}</ref> To Agastya, the star is said to be the 'cleanser of waters', and its rising coincides with the calming of the waters of the [[Indian Ocean]]. Canopus is described by [[Pliny the Elder]] and [[Gaius Julius Solinus]] as the largest, brightest and only source of [[starlight]] for navigators near [[Tamraparni]] island (ancient Sri Lanka) during many nights.<ref>{{cite book |last1=Pridham |first1=Charles |title=An Historical, Political, and Statistical Account of Ceylon and Its Dependencies |date=1849 |publisher=T. and W. Boone |page=7 |url=https://books.google.com/books?id=O4aqHOMSJdYC&pg=PR19-IA5|language=en}}</ref><ref name="Frawley 1993"/><ref>{{cite book |last1=Elder |first1=Pliny the |title=Delphi Complete Works of Pliny the Elder (Illustrated) |date=2015 |publisher=Delphi Classics |url=https://books.google.com/books?id=OrJ0CgAAQBAJ&pg=PA343|language=en}}</ref>
===Iran (Persia)===
Canopus, known as Suhail (سُهَيْل) in [[Arabic]] and Soheil (سهیل) in [[Persian language|Farsi]], holds significant cultural importance in Iran. Its visibility in [[Iran]] varies due to the country's range of latitudes. For instance, in the [[Alborz Mountains]], at approximately 36°N latitude, Canopus rises just one degree above the southern horizon, making it a rare sight. This rarity has led to the Persian expression "ستاره سهیل شدن" ("becoming the star Soheil"), used to describe someone who is seldom seen or elusive. The term "Soheil" symbolizes rarity in [[Persian literature]], reflecting the star's infrequent visibility in the region.<ref>{{cite web 
| url = https://twanight.org/gallery/canopus-from-the-northern-limit-of-visibility/
| title = Canopus from the Northern Limit of Visibility
| website = The World at Night (TWAN)
| date = 
| access-date = 6 February 2025
| author = 
| publisher = TWAN
| language = English
}}</ref><ref>{{cite web
| url = https://pasargadian1.blogfa.com/post/48
| title = ستارهٔ سهیل در فرهنگ و ادب فارسی
| website = Pasargadian Blog
| date = 
| access-date = 6 February 2025
| author = 
| publisher = Blogfa
| language = Persian
}}</ref>
[[Ferdowsi]] references Canopus in his poetry, associating it with [[Yemen]]:
<poem>
ز سر تا بپایش گلست و سمن  
به سرو سهی بر سهیل یمن  
</poem>
Ze sar tā be-pāyash golast o saman  
Be sarv-e sehī bar Sohayl-e Yaman  
<poem>
From head to toe, she is adorned with flowers and jasmine, 
Like the tall cypress under the Canopus of Yemen.
</poem>
Ferdowsi uses Canopus as a metaphor for beauty and rarity, linking it to Yemen, where the star is visible.<ref>{{cite book | title=Shahnameh | author=Ferdowsi | language=fa}}</ref><ref>{{cite web | url = https://profarsi.com/ferdowsi-famous-poems-in-english-and-farsi/ | title = Ferdowsi famous poems in English and Farsi | website = ProFarsi | access-date = 6 February 2025 | language = fa }}</ref>
The star's name also appears in Persian literary works, such as Anvār-i Suhaylī (انوار سهیلی) ("Lights of Canopus"), a 15th-century Persian adaptation of [[Kalīla wa-Dimna]] (کلیله و دمنه) (itself an earlier Persian translation of the ancient Indian [[Panchatantra]]).These works highlight the cultural significance of Canopus in Persian literature.<ref>{{cite web
| url = https://blogs.bl.uk/asian-and-african/2016/11/the-anvar-i-suhayli-or-lights-of-canopus.html
| title = The Anvār-i Suhaylī or "Lights of Canopus"
| website = British Library Asian and African Studies Blog
| date = 4 November 2016
| access-date = 6 February 2025
| author = Ursula Sims-Williams
| publisher = British Library
| language = English
}}</ref>
===China===
Canopus was described as Shou Xing, the Star of Longevity, in the ''Shiji'' ([[Records of the Grand Historian]]) completed in 94 BC by Chinese historian [[Sima Qian]].<ref name=fong83>{{cite journal | title=The Iconography of the Popular Gods of Happiness, Emolument, and Longevity (Fu Lu Shou) | first=Mary H. |last=Fong | journal=Artibus Asiae | volume= 44 | issue= 2/3 | year=1983| pages= 159–199 | doi= 10.2307/3249596| jstor=3249596 }}</ref> Drawing on sources from the [[Warring States period]], he noted it to be the southern counterpart of [[Sirius]],<ref name="IDP"/> and wrote of a sanctuary dedicated to it established by Emperor [[Qin Shi Huang]] between 221 and 210 BC. During the [[Han dynasty]], the star was auspicious, its appearance in the southern sky heralding peace and absence war.<ref name=fong83/> From the imperial capital [[Chang'an]], the star made a low transit across the southern sky, indicating true south to observers, and was often obscured by clouds.<ref name=baumann19>{{cite journal | title=The White Old Man: Géluk-Mongolian Canopus Allegory and the Existence of God | first=Brian | last=Baumann | journal= Central Asiatic Journal | volume= 62 | issue= 1 | year=2019| pages= 35–68 | doi=10.13173/centasiaj.62.1.0035| s2cid=213083544 }}</ref> During this time it was also equated with [[Old Man of the South Pole]] (in {{zh|c=南极老人|p=Nanji Lǎorén}})<ref name=fong83/> Under this name, Canopus appears (albeit misplaced northwards) on the medieval Chinese manuscript the [[Dunhuang Star Chart]], although it cannot be seen from the Chinese capital of [[Chang'an]].<ref name="IDP">{{cite journal|bibcode=2009JAHH...12...39B|arxiv=0906.3034|title=The Dunhuang Sky: A Comprehensive Study of the Oldest Known Star Atlas|volume=12|issue=1|pages=39–59|last1=Bonnet-Bidaud|first1=Jean-Marc |last2=Praderie|first2=Françoise |last3=Whitfield|first3=Susan |author-link=Susan Whitfield |journal=The International Dunhuang Project: The Silk Road Online|year=2009}}</ref> The Chinese astronomer [[Yi Xing]] had journeyed south to chart Canopus and other far southern stars in 724 AD.<ref>{{cite book|last=Needham|first=Joseph|title=Science and Civilisation in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth|publisher=Cambridge University Press|location=Cambridge, United Kingdom|date=1959|pages=274|isbn=0521058015}}</ref> Its personification as the Old Man Star was popularised in the [[Tang dynasty]], where it appeared often in poetry and memorials. Later still, during the [[Ming dynasty]], the star was established as one of the [[Sanxing (deities)|Three Stars]] (Fu Lo Shou), appearing frequently in art and literature of the time.<ref name=fong83/> This symbolism spread into neighbouring cultures in Asia.<ref name=baumann19/>
In Japan, Canopus is known as ''Mera-boshi'' and ''Roujin-sei'' (the old man star),<ref>{{cite conference |url=http://www2.tba.t-com.ne.jp/october-country/ips96/japanese_star.html |title=Stellar Iconology and Astronomical Folklore in Japan |author=Takao Ibaraki |book-title=International Planetarium Society (IPS) Conferences 1996 |publisher=International Planetarium Society |location=Osaka |date=14 July 1996 |access-date=25 February 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120326195757/http://www2.tba.t-com.ne.jp/october-country/ips96/japanese_star.html |archive-date=2012-03-26 }}</ref> and in Mongolia, it was personified as the White Old Man.<ref name=fong83/> Although the link was known in Tibet, with names such as ''Genpo karpo'' (''Rgan po dkar po'') or ''Genkar'' (''Rgan dkar'') "White Old Man", the symbolism was not popular. Instead, Canopus was more commonly named ''Karma Rishi སྐར་མ་རི་ཥི།'', derived from Indian mythology. Tibetans celebrated the star's heliacal rising with ritual bathing and associated it with morning dew.<ref name=baumann19/>

===Polynesia===
Bright stars were important to the ancient [[Polynesian culture|Polynesians]] for navigation between the many islands and atolls of the Pacific Ocean. Low on the horizon, they acted as stellar compasses to assist mariners in charting courses to particular destinations. Canopus served as the southern wingtip of a "Great Bird" constellation called ''Manu'', with Sirius as the body and [[Procyon]] the northern wingtip, which divided the Polynesian night sky into two hemispheres.<ref name="Holberg">{{cite book | last=Holberg | first=J.B. | title=Sirius: Brightest Diamond in the Night Sky | date=2007 | publisher=Praxis Publishing | location=Chichester, UK | isbn=978-0-387-48941-4 | pages=[https://archive.org/details/siriusbrightestd0000holb/page/25 25–26] | url=https://archive.org/details/siriusbrightestd0000holb/page/25 }}</ref> The [[Hawaiian people]] called Canopus ''Ke Alii-o-kona-i-ka-lewa'', "The chief of the southern expanse"; it was one of the stars used by [[Hawaiʻiloa]] and Ki when they traveled to the [[Southern Ocean]].{{sfn|Makemson|1941|p=198}}

The [[Māori people]] of [[New Zealand|New Zealand/Aotearoa]] had several names for Canopus. ''[[Ariki]]'' ("High-born"), was known as a solitary star that appeared in the east, prompting people to weep and chant.{{sfn|Makemson|1941|p=201}} They also named it ''[[Atutahi]]'', ''Aotahi'' or ''Atuatahi'', "Stand Alone".<ref>p. 419, [https://books.google.com/books?id=p7dR2w1Wv2sC ''Mythology: Myths, Legends and Fantasies'']{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}, Janet Parker, Alice Mills, Julie Stanton, Durban, Struik Publishers, 2007.</ref> Its solitary nature indicates it is a ''[[Tapu (Polynesian culture)|tapu]]'' star, as ''tapu'' people are often solitary. Its appearance at the beginning of the ''Maruaroa'' season foretells the coming winter; light rays to the south indicate a cold wet winter, and to the north foretell a mild winter. Food was offered to the star on its appearance.<ref name="Best22">{{cite book|last=Best|first=Elsdon|title=Astronomical Knowledge of the Maori: Genuine and Empirical|publisher=Dominion Museum|location=Wellington, New Zealand|date=1922|pages=34–35|url=http://nzetc.victoria.ac.nz/tm/scholarly/tei-BesAstro-t1-body-d1-d6-d4.html}}</ref> This name has several mythologies attached to it. One story tells of how Atutahi was left outside the basket representing the [[Milky Way]] when [[Tāne]] wove it. Another related myth about the star says that Atutahi was the first-born child of [[Rangi and Papa|Rangi]], who refused to enter the Milky Way and so turned it sideways and rose before it. The same name is used for other stars and constellations throughout Polynesia.{{sfn|Makemson|1941|pp=200–202}} ''Kapae-poto'', "Short horizon", referred to it rarely setting as seen in New Zealand;{{sfn|Makemson|1941|p=217}} ''Kauanga'' ("Solitary") was the name for Canopus only when it was the last star visible before sunrise.{{sfn|Makemson|1941|p=218}}

The people of the [[Society Islands]] had two names for Canopus, as did the [[Tuamotu]] people. The Society Islanders called Canopus ''Taurua-e-tupu-tai-nanu'', "Festivity-whence-comes-the-flux-of-the-sea", and ''Taurua-nui-o-te-hiti-apatoa'' "Great-festivity-of-the-border-of-the-south",{{sfn|Makemson|1941|p=259}} and the Tuamotu people called the star ''Te Tau-rari'' and ''Marere-te-tavahi'', the latter said to be the true name for the former, "He-who-stands-alone".{{sfn|Makemson|1941|p=229}}

===Africa===
In the [[Guanches|Guanche]] mythology of the island of [[Tenerife]] (Spain), the star Canopus was linked with the goddess [[Chaxiraxi]].<ref name="Rumeu">{{cite book|author=Antonio Rumeu de Armas|title=La conquista de Tenerife, 1494–1496|url=https://books.google.com/books?id=Ck4BAAAAMAAJ|year=1975|publisher=Aula de Cultura de Tenerife|isbn=9788450071078}}</ref>

The [[Tswana people]] of [[Botswana]] knew Canopus as ''Naka''. Appearing late in winter skies, it heralded increasing winds and a time when trees lose their leaves. Stock owners knew it was time to put their sheep with rams.<ref>{{cite journal|last=Clegg|first=Andrew|date=1986|title=Some Aspects of Tswana Cosmology|journal=Botswana Notes and Records|volume=18|pages=33–37|jstor=40979758 }}</ref> In southern Africa, the Sotho, Tswana and Venda people called Canopus ''Naka'' or ''Nanga'', “the Horn Star”, while the Zulu and Swazi called it ''inKhwenkwezi'' "Brilliant star". It appears in the predawn sky in the third week of May. According to the Venda, the first person to see Canopus would blow a ''phalaphala'' horn from the top of a hill, getting a cow for a reward. The Sotho chiefs also awarded a cow, and ordered their medicine men to roll bone dice and read the fortune for the coming year.<ref name=snedegar95>{{cite journal |last1=Snedegar |first1=K.V. |title=Stars and seasons in Southern Africa |journal=Vistas in Astronomy |date=1995 |volume=39 |issue=4 |pages=529–38 |doi=10.1016/0083-6656(95)00008-9|bibcode=1995VA.....39..529S }}</ref> To the [[ǀXam language|ǀXam]]-speaking [[Bushmen]] of South Africa, Canopus and Sirius signalled the appearance of termites and flying ants. They also believed that stars had the power to cause death and misfortune, and they would pray to [[Sirius]] and Canopus in particular to impart good fortune or skill.<ref>{{cite journal| title="The Sky's Things", <nowiki>|</nowiki>xam Bushman 'Astrological Mythology' as recorded in the Bleek and Lloyd Manuscripts |last1=Hollman|first1=J. C.|journal=African Sky|volume= 11|page=8 |bibcode=2007AfrSk..11....8H|year = 2007 }}</ref> The [[ǃKung people]] of the [[Kalahari Desert]] in Botswana held Canopus and Capella to be the horns of ''tshxum'' (the Pleiades), the appearance of all three marking the end of the dry season and start of the rainy season.<ref>{{cite journal |last1=Marshall |first1=Lorna |title=Two Ju/ wa constellations |journal=Botswana Notes & Records |date=1975 |volume=7 |issue=1 |pages=153–159 | issn=0525-5090 |url=https://journals.co.za/docserver/fulltext/botnotes/7/1/548.pdf?expires=1590793041&id=id&accname=guest&checksum=3204085F9555AD9D083799E1F38E3AED}}</ref>

===Americas===
The [[Navajo]] observed the star and named it ''Maʼii Bizòʼ'', the “Coyote Star”. According to legend, Maʼii (Coyote) took part in the naming and placing of the star constellations during
the creation of the universe. He placed Canopus directly south, naming it after himself.<ref name="Maryboy">Maryboy, Nancy D. (2004). ''A Guide to Navajo Astronomy.'' Indigenous Education Institute : Bluff, Utah.</ref>

The [[Kalapalo]] people of [[Mato Grosso]] state in Brazil saw Canopus and [[Procyon]] as ''Kofongo'' "Duck", with [[Castor (star)|Castor]] and [[Pollux (star)|Pollux]] representing his hands. The asterism's appearance signified the coming of the rainy season and increase in [[manioc]], a food staple fed to guests at feasts.<ref name="basso87">{{cite book|last=Basso|first=Ellen B. |title=In Favor of Deceit: A Study of Tricksters in an Amazonian Society|publisher=University of Arizona Press|location=Tucson, Arizona|date=1987|page=[https://archive.org/details/infavorofdeceits0000bass/page/360 360]|isbn=0816510229|url=https://archive.org/details/infavorofdeceits0000bass|url-access=registration}}</ref>

===Australia===
Canopus is identified as the moiety ancestor ''Waa'' "Crow" to some [[Koori]] people in southeastern Australia.<ref>{{cite book|last=Mudrooroo|title=Aboriginal mythology: an A-Z spanning the history of aboriginal mythology from the earliest legends to the present day|publisher=HarperCollins|location=London|date=1994|page=27|isbn=1-85538-306-3}}</ref> The Boorong people of northwestern Victoria recalled that ''War'' (Canopus) was the brother of ''Warepil'' (Sirius), and that he brought fire from the heavens and introduced it to humanity. His wife was ''Collowgullouric War'' ([[Eta Carinae]]).<ref name=hamacher10>{{cite journal|last1=Hamacher|first1=Duane W. |last2=Frew|first2=David J. |date=2010|title= An Aboriginal Australian Record of the Great Eruption of Eta Carinae|journal=Journal of Astronomical History & Heritage |volume=13|issue=3|pages= 220–34|doi=10.3724/SP.J.1440-2807.2010.03.06 |bibcode=2010JAHH...13..220H|arxiv = 1010.4610 |s2cid=118454721 }}</ref> The Pirt-Kopan-noot people of western Victoria tell of ''Waa'' "Crow" falling in love with a queen, ''Gneeanggar'' "Wedge-tailed Eagle"  (Sirius) and her six attendants (the Pleiades). His advances spurned, he hears that the women are foraging for grubs and so transforms himself into a grub. When the women dig him out, he changes into a giant and carries her off.<ref>Mudroodoo, p. 55.</ref>

The Kulin people know Canopus as ''Lo-an-tuka''.<ref name=hamacher10/> Objects in the sky are also associated with states of being for some tribes; the Wailwun of northern New South Wales know Canopus as ''Wumba'' "deaf", alongside Mars as ''Gumba'' "fat" and Venus as ''Ngindigindoer'' "you are laughing".<ref name="noctuary">{{cite book|last=Johnson|first=Diane|title=Night skies of aboriginal Australia: a noctuary|publisher=University of Sydney|location=Darlington, New South Wales|date=1998|page=[https://archive.org/details/nightskiesofabor0000john/page/84 84]|isbn=1-86451-356-X|url-access=registration|url=https://archive.org/details/nightskiesofabor0000john/page/84}}</ref>

Tasmanian aboriginal lore holds that Canopus is ''Dromerdene'', the brother of ''Moinee''; the two fought and fell out of the sky, with ''Dromerdene'' falling into Louisa Bay in southwest Tasmania.<ref name="haynes2000">{{cite book|last=Haynes|first=Ros D.|title= Astronomy and the Dreaming: The Astronomy of the Aboriginal Australians. Astronomy Across Cultures: The History of Non-Western Astronomy|publisher=Kluwer Academic Publishers|date=2000|page=57|doi=10.1007/978-94-011-4179-6_3}}</ref> Astronomer [[Duane Hamacher]] has identified Canopus with ''Moinee'' in a paper dating Tasmanian Aboriginal oral tradition to the late Pleistocene,<ref name=hamacher23>{{cite journal|last1=Hamacher|first1=Duane|last2=Nunn|first2=Patrick|date=2023|title=The archaeology of orality: Dating Tasmanian Aboriginal oral traditions to the Late Pleistocene|journal=Journal of Archaeological Science|volume=159 |doi=10.1016/j.jas.2023.105819|doi-access=free|bibcode=2023JArSc.159j5819H }}</ref> when Canopus was much closer to the South [[celestial pole]].

===Legacy===
[[File:HMS Glory LOC ggbain.17135.jpg|thumb|right|[[Canopus-class battleship]] HMS Glory]]

Canopus appears on the [[flag of Brazil]], symbolising the state of [[Goiás]].<ref>{{cite web
 |title=Astronomy of the Brazilian Flag 
 |url=https://flagspot.net/flags/br_astro.html 
 |publisher=FOTW Flags Of The World website 
}}</ref>

Two U.S. Navy [[submarine tender]]s have been named after Canopus, the [[USS Canopus (AS-9)|first]] serving from 1922 to 1942 and the [[USS Canopus (AS-34)|second]] serving from 1965 to 1994.

The [[Royal Navy]] built nine [[Canopus-class ship of the line|Canopus-class ships of the line]] in the early 19th century, and six {{Sclass|Canopus|battleship|1}}s which entered services between 1899 and 1902.

There are at least two mountains named after the star: [[Mount Canopus]] in Antarctica; and Mount Canopus or Canopus Hill in [[Tasmania]], the location of the [[Canopus Hill Observatory|Canopus Hill astronomical observatory]].

=== In popular culture ===
* The fictional planet [[Arrakis]], of [[Frank Herbert]]'s 1965 novel ''[[Dune (novel)|Dune]],'' orbits Canopus.<ref>{{Cite web |date=2024-02-18 |title=Can you see Canopus, the 2nd-brightest star? |url=https://earthsky.org/brightest-stars/few-know-the-second-brightest-star-canopus/ |access-date=2024-03-05 |website=earthsky.org |language=en-US}}</ref>
{{clear}}
* Canopus is the home of superior and benevolent aliens in Doris Lessing's ''[[Canopus in Argos]]'' books.<ref>[https://archive.nytimes.com/www.nytimes.com/books/99/01/10/specials/lessing-space.html?_r=1 "Doris Lessing on Feminism, Communism and 'Space Fiction'"]</ref>
* Canopus is a system present in the video game [[Helldivers 2]], host to a desert world.

==See also==
*[[List of brightest stars]]
*[[List of most luminous stars]]
*[[List of nearest supergiants]]

==References==
{{Reflist|30em}}

===Bibliography===
* {{cite book | last = Makemson | first = Maud Worcester | date = 1941 | publisher = [[Yale University Press]] | title = The Morning Star Rises: an account of Polynesian astronomy | bibcode = 1941msra.book.....M }}
* {{cite book |title=The Brightest Stars: Discovering the Universe through the Sky's Most Brilliant Stars |last=Schaaf |first=Fred |year=2008 |publisher=John Wiley & Sons |location=Hoboken, NJ |isbn=978-0-471-70410-2 }}

{{Sky|06|23|57.1099|-|52|41|44.378|310}}

{{Carina (constellation)}}
{{Portal bar|Astronomy|Stars|Spaceflight|Outer space|Solar System}}
{{Authority control}}

{{DEFAULTSORT:Canopus}}
[[Category:Canopus| ]]
[[Category:Bayer objects|Carinae, Alpha]]
[[Category:Carina (constellation)]]
[[Category:A-type bright giants]]
[[Category:Henry Draper Catalogue objects|045348]]
[[Category:Hipparcos objects|030438]]
[[Category:Bright Star Catalogue objects|2326]]
[[Category:Durchmusterung objects]]
[[Category:Stars with proper names|Canopus]]