Editing Canis Major

{{Short description|Constellation in the southern celestial hemisphere}}
{{Redirect-multi|2|CMa|Great Dog|other uses|CMA (disambiguation)|and|Great Dog (disambiguation)}}
{{Featured article}}

{{Infobox constellation
| name = Canis Major
| abbreviation = CMa
| genitive = Canis Majoris
| pronounce = {{IPAc-en|ˌ|k|eɪ|n|ᵻ|s|_|ˈ|m|eɪ|dʒ|ər}} {{respell|KAY|niss|_|MAY|jər}}, genitive {{IPAc-en|ˌ|k|eɪ|n|ᵻ|s|_|m|ə|ˈ|dʒ|ɔːr|ᵻ|s}} {{respell|KAY|niss|_|mə|JOR|iss}}
| symbolism = the greater dog
| RA = {{RA|06|12.5}} to {{RA|07|27.5}}<ref name="boundary"/>
| dec = −11.03° to −33.25°<ref name="boundary"/>
| areatotal = 380
| arearank = 43rd
| numbermainstars = 8
| numberbfstars = 32
| numberstarsplanets = 7
| numberbrightstars = 5
| numbernearbystars = 1
| brighteststarname = [[Sirius]] (α CMa)
| starmagnitude = −1.46
| neareststarname = [[Sirius]] (α CMa)
| stardistancely = 8.60
| stardistancepc = 2.64
| numbermessierobjects = 1
| meteorshowers = 0
| bordering =
  {{plainlist |
* [[Monoceros]]
* [[Lepus (constellation)|Lepus]]
* [[Columba (constellation)|Columba]]
* [[Puppis]]
  }}
| latmax = [[60th parallel north|60]]
| latmin = [[South Pole|90]]
| month = February
| notes =
}}

'''Canis Major''' is a [[constellation]] in the [[southern celestial hemisphere]]. In the second century, it was included in [[Ptolemy]]'s 48 constellations, and is counted among the [[88 modern constellations]]. Its name is [[Latin]] for "greater dog" in contrast to [[Canis Minor]], the "lesser dog"; both figures are commonly represented as following the constellation of [[Orion (constellation)|Orion]] the hunter through the sky. The [[Milky Way]] passes through Canis Major and several [[open cluster]]s lie within its borders, most notably [[Messier 41|M41]].

Canis Major contains [[Sirius]], the [[brightest star]] in the night sky, known as the "dog star". It is bright because of its proximity to the [[Solar System]] and its [[intrinsic brightness]]. In contrast, the other bright stars of the constellation are stars of great distance and high [[luminosity]]. At magnitude 1.5, [[Epsilon Canis Majoris]] (Adhara) is the second-brightest star of the [[constellation]] and the brightest source of [[extreme ultraviolet]] radiation in the night sky. Next in brightness are the yellow-white supergiant [[Delta Canis Majoris|Delta]] (Wezen) at 1.8, the blue-white giant [[Beta Canis Majoris|Beta]] (Mirzam) at 2.0, blue-white supergiants [[Eta Canis Majoris|Eta]] (Aludra) at 2.4 and [[Omicron2 Canis Majoris|Omicron<sup>2</sup>]] at 3.0, and white spectroscopic binary [[Zeta Canis Majoris|Zeta]] (Furud), also at 3.0. The red hypergiant [[VY CMa]] is one of the [[List of largest known stars|largest stars known]], while the [[neutron star]] [[RX J0720.4-3125]] has a radius of a mere 5&nbsp;km.

== History and myths ==

=== In western astronomy ===
In ancient [[Mesopotamia]], Sirius, named KAK.SI.SA<sub>2</sub> by the [[Babylon]]ians, was seen as an arrow aiming towards Orion, while the southern stars of Canis Major and a part of [[Puppis]] were viewed as a bow, named BAN in the ''[[Babylonian star catalogues#Three Stars Each|Three Stars Each]]'' tablets, dating to around 1100 BC. In the later compendium of Babylonian astronomy and astrology titled ''[[MUL.APIN]]'', the arrow, Sirius, was also linked with the warrior [[Ninurta]], and the bow with [[Ishtar]], daughter of [[Enlil]].<ref name="rogers1998">{{cite journal | first=John H. | last=Rogers | year=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> Ninurta was linked to the later deity [[Marduk]], who was said to have slain the ocean goddess [[Tiamat]] with a great bow, and worshipped as the principal deity in Babylon.{{sfn|Wagman|2003|p=71}} The Ancient Greeks replaced the bow and arrow depiction with that of a dog.<ref name="rogers1998a">{{cite journal | first=John H. | last=Rogers | year=1998 | title=Origins of the Ancient Constellations: II. The Mediterranean Traditions | journal=Journal of the British Astronomical Association | volume=108 | issue=2| pages=79–89 | bibcode=1998JBAA..108...79R}}</ref>
[[File:Sirius 1.jpg|250px|thumb|right|[[Sirius A]], the brightest star in the night sky, lies in Canis Major.]]
In Greek Mythology, Canis Major represented the dog [[Laelaps (mythology)|Laelaps]], a gift from [[Zeus]] to [[Europa (mythology)|Europa]]; or sometimes the hound of [[Procris]], [[Diana (mythology)|Diana's]] nymph; or the one given by [[Eos|Aurora]] to [[Cephalus]], so famed for its speed that Zeus elevated it to the sky.{{sfn|Allen|1963|p=117}} It was also considered to represent one of Orion's hunting dogs,{{sfn|Ridpath|Tirion|2001|pp=98–99}} pursuing [[Lepus (constellation)|Lepus]] the [[Hare]] or helping Orion fight [[Taurus (constellation)|Taurus]] the Bull; and is referred to in this way by [[Aratus|Aratos]], [[Homer]] and [[Hesiod]]. The [[ancient Greeks]] refer only to one dog, but by [[ancient Rome|Roman]] times, [[Canis Minor]] appears as Orion's second dog. Alternative names include Canis Sequens and Canis Alter.{{sfn|Allen|1963|p=117}} Canis Syrius was the name used in the 1521 ''[[Alfonsine tables]]''.{{sfn|Allen|1963|p=117}}

The Roman myth refers to Canis Major as ''Custos Europae'', the dog guarding Europa but failing to prevent her abduction by [[Jupiter (mythology)|Jupiter]] in the form of a bull, and as ''[[Cerberus|Janitor Lethaeus]]'', "the watchdog".{{sfn|Allen|1963|p=118}} In medieval Arab astronomy, the constellation became ''al-Kalb al-Akbar'', "the Greater Dog", transcribed as ''Alcheleb Alachbar'' by 17th century writer [[Edmund Chilmead]]. Islamic scholar [[Abū Rayḥān al-Bīrūnī]] referred to Orion as  ''Kalb al-Jabbār'', "the Dog of the Giant".{{sfn|Allen|1963|p=117}} Among the [[Merazig]] of [[Tunisia]], shepherds note six constellations that mark the passage of the dry, hot season. One of them, called ''[[Merzem]]'', includes the stars of Canis Major and Canis Minor and is the herald of two weeks of hot weather.<ref>{{cite journal |title = A Review of African Ethno-Astronomy: With Particular Reference to Saharan Livestock-Keepers |last = Oxby |first = Claire |journal = [[La Ricerca Folklorica]] |date = October 1999 |pages = 57–58 | jstor = 1479768 |issue = 40|doi = 10.2307/1479768 }}</ref>
[[File:Canis Major on the Manuchihr Globe.jpg|thumb|Canis Major as depicted on the [[Abu al-Fath Manuchihr Khan|Manuchihr]] Globe made in [[Mashhad]] 1632–33 AD. Adilnor Collection, Sweden.]]

=== In non-western astronomy ===
[[File:Canis Major above Kuantan Night Sky.jpg|thumb|right|Canis Major, observed above Kuantan (north is towards top right)]]

In [[Chinese astronomy]], the modern constellation of [[Canis Major (Chinese astronomy)|Canis Major]] is located in the [[Vermilion Bird]] ({{lang-zh |c=南方朱雀 |p=Nán Fāng Zhū Què |labels=no }}), where the stars were classified in several separate [[Asterism (astronomy)|asterism]]s of stars. The Military Market ({{lang-zh |p=Jūnshì |c=軍市 |labels=no }}) was a circular pattern of stars containing [[Nu3 Canis Majoris|Nu<sup>3</sup>]], [[Beta Canis Majoris|Beta]], [[Xi1 Canis Majoris|Xi<sup>1</sup>]] and [[Xi2 Canis Majoris|Xi<sup>2</sup>]], and some stars from Lepus.{{sfn|Schlegel|1967|p=428}} The Wild Cockerel ({{lang-zh |p=Yějī |c=野雞 |labels=no }}) was at the centre of the Military Market, although it is uncertain which stars depicted what. Schlegel reported that the stars [[Omicron Canis Majoris|Omicron]] and [[Pi Canis Majoris]] might have been them,{{sfn|Schlegel|1967|p=430}} while Beta or [[Nu2 Canis Majoris|Nu<sup>2</sup>]] have also been proposed.<ref name="ridpathcma">{{cite web |url=http://www.ianridpath.com/startales/canismajor.html#chinese |work=Star Tales |title=Canis Major – the Greater Dog |last1=Ridpath |first1=Ian |access-date= 1 March 2014 }}</ref> [[Sirius]] was ''{{lang|zh-Latn|Tiānláng}}'' ({{lang|zh|天狼}}), the Celestial Wolf,{{sfn|Schlegel|1967|p=431}} denoting invasion and plunder.<ref name="ridpathcma"/> Southeast of the Wolf was the asterism ''{{lang|zh-Latn|Húshǐ}}'' ({{lang|zh|弧矢}}), the celestial Bow and Arrow, which was interpreted as containing [[Delta Canis Majoris|Delta]], [[Epsilon Canis Majoris|Epsilon]], [[Eta Canis Majoris|Eta]] and [[Kappa Canis Majoris]] and [[Delta Velorum]]. Alternatively, the arrow was depicted by [[Omicron2 Canis Majoris|Omicron<sup>2</sup>]] and Eta and aiming at Sirius (the Wolf), while the bow comprised Kappa, Epsilon, [[Sigma Canis Majoris|Sigma]], Delta and 164 Canis Majoris, and [[Pi Puppis|Pi]] and [[Omicron Puppis]].{{sfn|Schlegel|1967|p=434}}<!-- cites previous two sentences -->

Both the [[Māori people]] and the people of the [[Tuamotus]] recognized the figure of Canis Major as a distinct entity, though it was sometimes absorbed into other constellations. ''{{lang|mi|Te Huinga-o-Rehua}}'', also called ''{{lang|mi|Te Putahi-nui-o-Rehua}}'' and ''{{lang|mi|Te Kahui-Takurua}}'', ("The Assembly of {{lang|mi|Rehua}}" or "The Assembly of Sirius") was a Māori constellation that included both Canis Minor and Canis Major, along with some surrounding stars.{{sfn|Makemson|1941|p=212}}{{sfn|Makemson|1941|p=215}} Related was ''{{lang|mi|Taumata-o-Rehua}}'', also called ''{{lang|mi|Pukawanui}}'', the Mirror of {{lang|mi|Rehua}}, formed from an undefined group of stars in Canis Major.{{sfn|Makemson|1941|p=258}}{{sfn|Makemson|1941|p=247}} They called Sirius ''{{lang|mi|Rehua}}'' and ''{{lang|mi|Takarua}}'', corresponding to two of the names for the constellation, though ''{{lang|mi|Rehua}}'' was a name applied to other stars in various Māori groups and other Polynesian cosmologies.{{sfn|Makemson|1941|p=249}}{{sfn|Makemson|1941|p=254}} The Tuamotu people called Canis Major ''{{lang|pmt|Muihanga-hetika-o-Takurua}}'', "the abiding assemblage of {{lang|mi|Takarua}}".{{sfn|Makemson|1941|p=236}}

The Tharumba people of the [[Shoalhaven River]] saw three stars of Canis Major as ''{{lang|dhu|Wunbula}}'' (Bat) and his two wives ''{{lang|dhu|Murrumbool}}'' (Mrs Brown Snake) and ''{{lang|dhu|Moodtha}}'' (Mrs Black Snake); bored of following their husband around, the women try to bury him while he is hunting a wombat down its hole. He spears them and all three are placed in the sky as the constellation ''{{lang|dhu|Munowra}}''.<ref name="ridley1875">{{cite book |last=Ridley |first=William |title=Kámilarói, and other Australian languages |publisher=T. Richards, government printer |location=Sydney, New South Wales |year=1875 |edition=2nd |pages=144–45 |url=http://www.newcastle.edu.au/Resources/Divisions/Academic/Library/Cultural%20Collections/pdf/ridley1875.pdf |archive-url=https://web.archive.org/web/20140301195245/http://www.newcastle.edu.au/Resources/Divisions/Academic/Library/Cultural%20Collections/pdf/ridley1875.pdf |archive-date=2014-03-01 |url-status=live}}</ref> To the [[Wergaia|Boorong]] people of Victoria, [[Sigma Canis Majoris]] was ''{{lang|weg|Unurgunite}}'' (which has become the official name of this star<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 its flanking stars Delta and Epsilon were his two wives.<ref name=hamacher>{{cite journal |last1=Hamacher |first1=Duane W. |last2=Frew |first2=David J. |year=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 |arxiv=1010.4610 |bibcode=2010JAHH...13..220H |s2cid=118454721 }}</ref> The moon (''{{lang|weg|Mityan}}'', "[[native cat]]") sought to lure the further wife (Epsilon) away, but {{lang|weg|Unurgunite}} assaulted him and he has been wandering the sky ever since.<ref>{{cite book |last=Smyth |first=Robert Brough |title=The Aborigines of Victoria: with Notes Relating to the Habits of the Natives of other Parts of Australia and Tasmania |publisher=J. Ferres, government printer |location=Melbourne, Victoria |year=1878 |pages=[https://archive.org/details/aboriginesofvict01smyt/page/433 433]–34 |url=https://archive.org/details/aboriginesofvict01smyt }}</ref>

== Characteristics ==
Canis Major is a constellation in the [[Southern Hemisphere]]'s summer (or northern hemisphere's winter) sky, bordered by [[Monoceros]] (which lies between it and Canis Minor) to the north, Puppis to the east and southeast, [[Columba (constellation)|Columba]] to the southwest, and Lepus to the west. The three-letter abbreviation for the constellation, as adopted by the [[International Astronomical Union]] in 1922, is "CMa".<ref name="pa30_469">{{cite journal | last=Russell | first=Henry Norris | title=The New International Symbols for the Constellations | journal=[[Popular Astronomy (US magazine)|Popular Astronomy]] | volume=30 | pages=469–71 | bibcode=1922PA.....30..469R | year=1922}}</ref> The official constellation boundaries, as set by Belgian astronomer [[Eugène Delporte]] in 1930, are defined by a quadrilateral; in the [[equatorial coordinate system]], the [[right ascension]] coordinates of these borders lie between {{RA|06|12.5}} and {{RA|07|27.5}}, while the [[declination]] coordinates are between −11.03° and −33.25°.<ref name="boundary">{{cite journal | title=Canis Major, Constellation Boundary | journal=The Constellations | url=https://www.iau.org/public/themes/constellations/#cma | access-date=15 November 2012}}</ref> Covering 380 square degrees or 0.921% of the sky, it ranks 43rd of the 88 currently-recognized constellations in size.<ref name=bagnall>{{cite book |last=Bagnall |first=Philip M. |title=The Star Atlas Companion: What You Need to Know about the Constellations |publisher=Springer  |location=New York, New York |year=2012 |isbn=978-1-4614-0830-7 |pages=99–106|url=https://books.google.com/books?id=KcIg02TKW6QC&pg=PA105}}</ref>

== Features ==
[[Image:CanisMajorCC.jpg|thumb|left|The stars of Canis Major as they can be seen by the naked eye; lines have been added for clarity.]]

=== Stars ===
{{See also|List of stars in Canis Major}}
Canis Major is a prominent constellation because of its many bright stars. These include Sirius (Alpha Canis Majoris), the [[brightest star]] in the night sky, as well as three other stars above magnitude 2.0.{{sfn|Ridpath|Tirion|2001|pp=98–99}} Furthermore, two other stars are thought to have previously outshone all others in the night sky—Adhara (Epsilon Canis Majoris) shone at −3.99 around 4.7&nbsp;million years ago, and Mirzam (Beta Canis Majoris) peaked at −3.65 around 4.42&nbsp;million years ago. Another, [[NR Canis Majoris]], will be brightest at magnitude −0.88 in about 2.87&nbsp;million years' time.<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>

The German cartographer [[Johann Bayer]] used the Greek letters [[Alpha]] through [[Omicron]] to label the most prominent stars in the constellation, including three adjacent stars as Nu and two further pairs as Xi and Omicron,{{sfn|Wagman|2003|p=73}} while subsequent observers designated further stars in the southern parts of the constellation that were hard to discern from Central Europe.{{sfn|Wagman|2003|p=71}} Bayer's countryman [[Johann Elert Bode]] later added Sigma, Tau and Omega;{{sfn|Wagman|2003|p=74}} the French astronomer [[Nicolas Louis de Lacaille]] added lettered stars a to k (though none are in use today).{{sfn|Wagman|2003|p=74}}  [[John Flamsteed]] numbered 31 stars, with 3 Canis Majoris being placed by Lacaille into Columba as [[Delta Columbae]] (Flamsteed had not recognised Columba as a distinct constellation).{{sfn|Wagman|2003|p=368}} He also labelled two stars—his [[10 Canis Majoris|10]] and [[13 Canis Majoris]]—as Kappa<sup>1</sup> and Kappa<sup>2</sup> respectively, but subsequent cartographers such as [[Francis Baily]] and [[John Bevis]] dropped the fainter former star, leaving Kappa<sup>2</sup> as the sole Kappa.{{sfn|Wagman|2003|p=73}} Flamsteed's listing of Nu<sup>1</sup>, Nu<sup>2</sup>, Nu<sup>3</sup>, Xi<sup>1</sup>, Xi<sup>2</sup>, Omicron<sup>1</sup> and Omicron<sup>2</sup> have all remained in use.{{sfn|Wagman|2003|pp=73–74}}
[[File:Sidney Hall - Urania's Mirror - Canis Major, Lepus, Columba Noachi & Cela Sculptoris.jpg|thumb|300px|Canis Major as depicted in ''[[Urania's Mirror]]'', a set of constellation cards published in London c.1825. Next to it are Lepus and Columba (partly cut off).]]
Sirius is the [[List of brightest stars|brightest star in the night sky]] at [[apparent magnitude]] −1.46 and one of the [[List of nearest stars|closest stars to Earth]] at a distance of 8.6 [[light-year]]s. Its name comes from the Greek word for "scorching" or "searing". Sirius is also a [[binary star]]; its companion [[Sirius B]] is a [[white dwarf]] with a magnitude of 8.4–10,000 times fainter than Sirius A to observers on Earth.<ref>{{cite book | last=Holberg | first=J.B. | title=Sirius: Brightest Diamond in the Night Sky | year=2007 | publisher=Praxis Publishing | location=Chichester, United Kingdom | isbn=978-0-387-48941-4 | page=[https://archive.org/details/siriusbrightestd0000holb/page/214 214] | url=https://archive.org/details/siriusbrightestd0000holb/page/214 }}</ref> The two [[orbit]] each other every 50 years. Their closest approach last occurred in 1993 and they will be at their greatest separation between 2020 and 2025. Sirius was the basis for the [[ancient Egyptian calendar]].{{sfn|Ridpath|Tirion|2001|pp=98–99}} The star marked the Great Dog's mouth on Bayer's star atlas.{{sfn|Wagman|2003|p=504}}

Flanking Sirius are Beta and [[Gamma Canis Majoris]]. Also called Mirzam or Murzim, Beta is a blue-white [[Beta Cephei variable]] star of magnitude 2.0, which varies by a few hundredths of a magnitude over a period of six hours.<ref name=kaler>{{cite web| first1=James B. | last1=Kaler | title=Mirzam | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/mirzam.html | access-date=2 January 2012 |date=4 May 2007}}</ref> Mirzam is 500 light-years from Earth, and its traditional name means "the announcer", referring to its position as the "announcer" of Sirius, as it rises a few minutes before Sirius does.{{sfn|Ridpath|Tirion|2001|pp=98–99}} Gamma, also known as Muliphein, is a fainter star of magnitude 4.12, in reality a blue-white bright giant of [[spectral type]] B8IIe located 441 light-years from earth.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Gamma+CMa&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Gamma Canis Majoris – Star in Cluster |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 16 February 2014}}</ref> [[Iota Canis Majoris]], lying between Sirius and Gamma, is another star that has been classified as a Beta Cephei variable, varying from magnitude 4.36 to 4.40 over a period of 1.92 hours.<ref name=AAVSOiota>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5507 |title=Iota Canis Majoris |author =Watson, Christopher |date=4 January 2010 |work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=2 March 2014}}</ref> It is a remote blue-white [[supergiant star]] of spectral type B3Ib, around 46,000 times as luminous as the sun and, at 2500 light-years distant, 300 times further away than Sirius.<ref name=kaleriot>{{cite web| first1=James B. | last1=Kaler | title=Iota Canis Majoris | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/iotacma.html |date=26 February 2010 | access-date=2 March 2014}}</ref>

Epsilon, [[Omicron2 Canis Majoris|Omicron<sup>2</sup>]], Delta, and Eta Canis Majoris were called ''Al Adzari'' "the virgins" in medieval Arabic tradition.<ref>{{cite journal|last=Knobel|first=Edward B.|year=1895|title= Al Achsasi Al Mouakket, on a Catalogue of Stars in the Calendarium of|journal=[[Monthly Notices of the Royal Astronomical Society]]|volume=55|issue=8|pages=429–38|bibcode=1895MNRAS..55..429K|doi=10.1093/mnras/55.8.429|doi-access=free}}</ref> Marking the dog's right thigh on Bayer's atlas is Epsilon Canis Majoris,{{sfn|Wagman|2003|p=504}} also known as Adhara. At magnitude 1.5, it is the second-brightest star in Canis Major and the 23rd-brightest star in the sky. It is a blue-white supergiant of spectral type B2Iab, around 404 light-years from Earth.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=eps+CMa&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Epsilon Canis Majoris – Double Star  |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 16 February 2014}}</ref> This star is one of the brightest known extreme ultraviolet sources in the sky.<ref>{{cite journal |author1=Wilkinson, E. |author2=Green, J.C. |author3=McLean, R. |author4=Welsh, B.  | title=Extreme Ultraviolet Spectrum of ɛ Canis Majoris Between 600–920 Å |  journal=Bull. Am. Astron. Soc. | year=1996 | volume=28 | issue=2  | page=915 |  bibcode=1996BAAS...28..915W }}</ref> It is a binary star; the secondary is of magnitude 7.4. Its traditional name means "the virgins", having been transferred from the group of stars to Epsilon alone.<ref name="Kunitzsch">{{cite book |author1=Kunitzsch, Paul |author2=Smart, Tim |year = 2006 |title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |edition = 2nd rev. |publisher = [[New Track Media#Sky Publishing|Sky Pub]] |location = Cambridge, Massachusetts  |isbn = 978-1-931559-44-7 |page = 23}}</ref> Nearby is Delta Canis Majoris, also called Wezen. It is a yellow-white supergiant of spectral type F8Iab and magnitude 1.84, around 1605 light-years from Earth.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=delta+CMa&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Delta Canis Majoris – Variable Star  |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 16 February 2014}}</ref> With a traditional name meaning "the weight", Wezen is 17 times as massive and 50,000 times as luminous as the Sun. If located in the centre of the Solar System, it would extend out to Earth as its diameter is 200 times that of the Sun. Only around 10&nbsp;million years old, Wezen has stopped fusing hydrogen in its core. Its outer envelope is beginning to expand and cool, and in the next 100,000 years it will become a red supergiant as its core fuses heavier and heavier elements. Once it has a core of iron, it will collapse and explode as a [[supernova]].<ref name="Kalerdelta">{{cite web|url=http://stars.astro.illinois.edu/sow/wezen.html|title=Wezen|last=Kaler|first=James B.|work=Stars website|publisher=University of Illinois|access-date=17 February 2014}}</ref> Nestled between Adhara and Wezen lies Sigma Canis Majoris, known as Unurgunite to the Boorong and Wotjobaluk people,<ref name=hamacher/> a red supergiant of spectral type K7Ib that varies irregularly between magnitudes 3.43 and 3.51.<ref name=AAVSOsig>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5512 |title=Sigma Canis Majoris |author =Watson, Christopher |date=4 January 2010 |work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=24 February 2014}}</ref>

Also called Aludra, Eta Canis Majoris is a blue-white supergiant of spectral type B5Ia with a luminosity 176,000 times and diameter around 80 times that of the Sun.<ref>{{cite journal|author1=Jerzykiewicz, M. |author2=Molenda-Zakowicz, J. |year=2000|title=Empirical Luminosities and Radii of Early-Type Stars after Hipparcos|journal=Acta Astronomica|volume=50|pages=369–80 |url=http://acta.astrouw.edu.pl/Vol50/n3/pap_50_3_5.pdf |archive-url=https://web.archive.org/web/20191110135730/http://acta.astrouw.edu.pl/Vol50/n3/pap_50_3_5.pdf |archive-date=2019-11-10 |url-status=live|bibcode=2000AcA....50..369J}}</ref> Classified as an [[Alpha Cygni variable|Alpha Cygni type]] [[variable star]], Aludra varies in brightness from magnitude 2.38 to 2.48 over a period of 4.7 days.<ref name=AAVSOeta>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5506 |title=Eta Canis Majoris |author =Watson, Christopher |date=3 May 2013 |work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=5 February 2014}}</ref> It is located 1120 light-years away. To the west of Adhara lies 3.0-magnitude [[Zeta Canis Majoris]] or Furud, around 362 light-years distant from Earth.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Zeta+CMa&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Zeta Canis Majoris – Cepheid Variable |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 17 February 2014}}</ref> It is a spectroscopic binary, whose components orbit each other every 1.85 years, the combined [[stellar spectrum|spectrum]] indicating a main star of spectral type B2.5V.<ref name="Kalerzeta">{{cite web|url=http://stars.astro.illinois.edu/sow/furud.html|title=Furud |last=Kaler|first=James B.|work=Stars website|publisher=University of Illinois|access-date=17 February 2014|date = 2 February 2007}}</ref>

Between these stars and Sirius lie [[Omicron1 Canis Majoris|Omicron<sup>1</sup>]], Omicron<sup>2</sup>, and [[Pi Canis Majoris]]. Omicron<sup>2</sup> is a massive supergiant star about 21 times as massive as the Sun.<ref name=mnras410_1_190>{{cite journal | last1=Tetzlaff | first1=N. | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M. | title=A Catalogue of Young Runaway Hipparcos Stars within 3 kpc from the Sun | journal=Monthly Notices of the Royal Astronomical Society | volume=410 | issue=1 | pages=190–200 |date=January 2011 | doi=10.1111/j.1365-2966.2010.17434.x | doi-access=free | bibcode=2011MNRAS.410..190T |arxiv = 1007.4883| s2cid=118629873 }}</ref> Only 7&nbsp;million years old,<ref name=mnras410_1_190/> it has exhausted the supply of hydrogen at its core and is now processing helium.<ref name=kaleromi2>{{cite web | first1=James B. | last1=Kaler | title=Omicron-2 Canis Majoris | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/omi2cma.html | access-date=24 February 2014 }}</ref> It is an Alpha Cygni variable that undergoes periodic non-radial pulsations, which cause its brightness to cycle from magnitude 2.93 to 3.08 over a 24.44-day interval.<ref name=aaa507_2_11411201>{{cite journal | last1=Lefèvre | first1=L. | last2=Marchenko | first2=S. V. | last3=Moffat | first3=A. F. J. | last4=Acker | first4=A. | title=A systematic study of variability among OB-stars based on HIPPARCOS photometry | journal=Astronomy and Astrophysics | volume=507 | issue=2 | pages=1141–1201 |date=November 2009 | doi=10.1051/0004-6361/200912304 | bibcode=2009A&A...507.1141L | doi-access=free }}</ref> Omicron<sup>1</sup> is an orange [[stellar classification|K-type]] supergiant of spectral type K2.5Iab that is an [[irregular variable]] star, varying between apparent magnitudes 3.78 and 3.99.<ref name=AAVSOomi>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5510 |title=Omicron1 Canis Majoris |author=Watson, Christopher|date=4 January 2010|work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=15 February 2014}}</ref> Around 18 times as massive as the Sun, it shines with 65,000 times its [[luminosity]].<ref name=kaleromi1>{{cite web| first1=James B. | last1=Kaler | title=Omicron1 Canis Majoris | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/omi1cma.html | access-date=24 February 2014}}</ref>

North of Sirius lie [[Theta Canis Majoris|Theta]] and [[Mu Canis Majoris]], Theta being the most northerly star with a Bayer designation in the constellation.<ref name="Kalertheta">{{cite web|url=http://stars.astro.illinois.edu/sow/thetacma.html|title=Theta Canis Majoris |last=Kaler|first=James B.|work=Stars website|publisher=University of Illinois|access-date=18 February 2014|date = 8 March 2013}}</ref> Around 8&nbsp;billion years old, it is an orange giant of spectral type K4III that is around as massive as the Sun but has expanded to 30 times the Sun's diameter.<ref name=aaa458_2_609>{{cite journal | last1=da Silva | first1=L. | last2=Girardi | first2=L. | last3=Pasquini | first3=L. | last4=Setiawan | first4=J. | last5=von der Lühe | first5=O. | last6=de Medeiros | first6=J.R. | last7=Hatzes | first7=A. | last8=Döllinger | first8=M.P. | last9=Weiss | first9=A. | title=Basic Physical Parameters of a Selected Sample of Evolved Stars | journal=Astronomy and Astrophysics | volume=458 | issue=2 | pages=609–23 |year=2006 | doi=10.1051/0004-6361:20065105 | bibcode=2006A&A...458..609D |arxiv = astro-ph/0608160 | s2cid=9341088 }}</ref> Mu is a multiple star system located around 1244 light-years distant,<ref name=simbadmu/> its components discernible in a small telescope as a 5.3-magnitude yellow-hued and 7.1-magnitude bluish star.<ref name="turnleft">{{cite book|last=Consolmagno|first=Guy |title=Turn Left at Orion: Hundreds of Night Sky Objects to See in a Home Telescope – and How to Find Them|publisher=Cambridge University Press|location=Cambridge, United Kingdom|year=2011|page=81|isbn=978-1-139-50373-0|url=https://books.google.com/books?id=h3712RgWkOYC&pg=PA80}}</ref> The brighter star is a giant of spectral type K2III,<ref name=simbadmu>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=18+CMa&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = 18 Canis Majoris |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 18 February 2014}}</ref> while the companion is a main sequence star of spectral type B9.5V.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%40929727&Name=HD%20%2051251&submit=submit |title = HD 51251 – Star in double system  |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 18 February 2014}}</ref> [[Nu1 Canis Majoris|Nu<sup>1</sup> Canis Majoris]] is a yellow-hued giant star of magnitude 5.7, 278 light-years away; it is at the threshold of naked-eye visibility. It has a companion of magnitude 8.1.{{sfn|Ridpath|Tirion|2001|pp=98–99}}

At the southern limits of the constellation lie Kappa and [[Lambda Canis Majoris]]. Although of similar spectra and nearby each other as viewed from Earth, they are unrelated.<ref name=bagnall/> Kappa is a [[Shell star|Gamma Cassiopeiae variable]] of spectral type B2Vne,<ref name=AAVSOkap>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5508 |title=Kappa Canis Majoris |author =Watson, Christopher |date=4 January 2010 |work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=24 February 2014}}</ref> which brightened by 50% between 1963 and 1978, from magnitude 3.96 or so to 3.52.<ref name=kalerkap>{{cite web | first1=James B. | last1=Kaler | title=Kappa Canis Majoris | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/kappacma.html | date=1 March 2013 | access-date=24 February 2014 | archive-url=https://web.archive.org/web/20170211102341/http://stars.astro.illinois.edu/sow/kappacma.html | archive-date=11 February 2017 | url-status=dead }}</ref> It is around 659 light-years distant.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=kappa+Canis+Majoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Kappa Canis Majoris – Be Star  |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 2 March 2014}}</ref> Lambda is a blue-white [[stellar classification|B-type]] [[main sequence|main sequence dwarf]] with an apparent magnitude of 4.48 located around 423 light-years from [[Earth]].<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Lambda+Canis+Majoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Lambda Canis Majoris – Star  |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 2 March 2014}}</ref> It is 3.7 times as wide as and 5.5 times as massive as the Sun, and shines with 940 times its luminosity.<ref name="Kalertheta"/>

[[File:VLT image of the surroundings of VY Canis Majoris seen with SPHERE.jpg|thumb|[[Very Large Telescope]] image of the surroundings of [[VY Canis Majoris]]]]
Canis Major is also home to many variable stars. [[EZ Canis Majoris]] is a [[Wolf–Rayet star]] of spectral type WN4 that varies between magnitudes 6.71 and 6.95 over a period of 3.766 days; the cause of its variability is unknown but thought to be related to its stellar wind and rotation.<ref name=StLouis1995>The IUE Mega Campaign: Wind Structure and Variability of HD 50896 (WN5) ''Astrophysical Journal Letters'' '''452''' #1, pp. L57 (October 1995) {{bibcode|1995ApJ...452L..57S}}</ref> [[VY Canis Majoris]] is a remote [[red hypergiant]] located approximately 3,800 light-years away from [[Earth]]. It is one of [[List of largest stars|largest stars known]] (sometimes described as the largest known)<ref name=Alcolea>{{cite journal |doi=10.1051/0004-6361/201321683 |title=HIFISTARSHerschel/HIFI observations of VY Canis Majoris |journal=Astronomy & Astrophysics |volume=559 |pages=A93 |year=2013 |last1=Alcolea |first1=J |last2=Bujarrabal |first2=V |last3=Planesas |first3=P |last4=Teyssier |first4=D |last5=Cernicharo |first5=J |last6=De Beck |first6=E |last7=Decin |first7=L |last8=Dominik |first8=C |last9=Justtanont |first9=K |last10=De Koter |first10=A |last11=Marston |first11=A. P |last12=Melnick |first12=G |last13=Menten |first13=K. M |last14=Neufeld |first14=D. A |last15=Olofsson |first15=H |last16=Schmidt |first16=M |last17=Schöier |first17=F. L |last18=Szczerba |first18=R |last19=Waters |first19=L. B. F. M |arxiv=1310.2400 |bibcode=2013A&A...559A..93A |s2cid=55758451 }}</ref> and is also [[List of most luminous stars|one of the most luminous]] with a radius varying from 1,420 to 2,200 times the Sun's radius, and a luminosity around 300,000 times greater than the Sun. Its current mass is about 17 ± 8 solar masses, having shed material from an initial mass of 25–32 solar masses.<ref name="Wittkowski_vlti">{{cite journal | doi = 10.1051/0004-6361/201219126 | last1 = Wittkowski | first1 = M. | last2 = Hauschildt | first2 = P.H. | last3 = Arroyo-Torres | first3 = B. | last4 = Marcaide | first4 = J.M. | title = Fundamental Properties and Atmospheric Structure of the Red Supergiant VY CMa based on VLTI/AMBER spectro-interferometry | journal = Astronomy & Astrophysics | volume = 540 | pages = L12 | year = 2012 | bibcode=2012A&A...540L..12W|arxiv=1203.5194| s2cid = 54044968 }}</ref><ref name=kaminski>{{cite journal|bibcode=2013A&A...551A.113K|title=Pure rotational spectra of TiO and TiO<sub>2</sub> in VY Canis Majoris|journal=Astronomy and Astrophysics|volume=551|issue=2013|pages=A113|last1=Kamiński|first1=T|last2=Gottlieb|first2=C. A|last3=Menten|first3=K. M|last4=Patel|first4=N. A|last5=Young|first5=K. H|last6=Brünken|first6=S|last7=Müller|first7=H. S. P|last8=McCarthy|first8=M. C|last9=Winters|first9=J. M|last10=Decin|first10=L|year=2013|arxiv=1301.4344|doi=10.1051/0004-6361/201220290|s2cid=59038056}}</ref><!-- cites previous 3.5 sentences --> VY CMa is also surrounded by a red [[reflection nebula]] that has been made by the material expelled by the strong stellar winds of its central star. [[W Canis Majoris]] is a type of red giant known as a [[carbon star]]—a semiregular variable, it ranges between magnitudes 6.27 and 7.09 over a period of 160 days.<ref name=AAVSOW>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5159 |title=W Canis Majoris |author =Otero, Sebastian Alberto |date=7 November 2011 |work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=12 March 2014}}</ref> A cool star, it has a surface temperature of around 2,900 K and a radius 234 times that of the Sun, its distance estimated at 1,444–1,450 light-years from Earth.<ref name="vanBelle13">{{cite journal|author1=van Belle, Gerard T. |author2=Paladini, Claudia |author3=Aringer, Bernhard |author4=Hron, Josef |author5=Ciardi, David |year=2013|title=The PTI Carbon Star Angular Size Survey: Effective Temperatures and Non-sphericity|journal=The Astrophysical Journal|volume=775|issue=1|pages=45|arxiv = 1307.6585 |bibcode = 2013ApJ...775...45V |doi = 10.1088/0004-637X/775/1/45 |s2cid=43847096 }}</ref> At the other extreme in size is [[RX J0720.4-3125]], a [[neutron star]] with a radius of around 5&nbsp;km.<ref name="Hohle">{{cite journal|author1=Hohle, M.M. |author2=Haberl, F. |author3=Vink, J. |author4=de Vries, C.P. |author5=Turolla, R. |author6=Zane, S. |author7=Méndez, M. |title = The Continued Spectral and Temporal Evolution of RX J0720.4-3125 | journal = Monthly Notices of the Royal Astronomical Society |volume = 423 |issue = 2 |pages= 1194–99 |bibcode=2012MNRAS.423.1194H  |arxiv = 1203.3708 |doi = 10.1111/j.1365-2966.2012.20946.x |year=2012 |doi-access=free |s2cid=55696761 }}</ref> Exceedingly faint, it has an apparent magnitude of 26.6.<ref name="Kaplan">{{cite journal|author1=Kaplan, D.L. |author2=van Kerkwijk, M.H. |author3=Marshall, H.L. |author4=Jacoby, B.A. |author5=Kulkarni, S. R. |author6=Frail, D.A. |year=2003|title=The Nearby Neutron Star RX J0720.4-3125 from Radio to X-rays|journal=The Astrophysical Journal|volume=590|issue=2 |pages=1008–1019 |doi=10.1086/375052|arxiv = astro-ph/0303126 |bibcode = 2003ApJ...590.1008K |s2cid=17115753 }}</ref> Its spectrum and temperature appear to be mysteriously changing over several years. The nature of the changes are unclear, but it is possible they were caused by an event such as the star's absorption of an [[accretion disc]].<ref name="Hohle"/>

[[Tau Canis Majoris]] is a [[Beta Lyrae variable|Beta Lyrae-type]] eclipsing multiple star system that varies from magnitude 4.32 to 4.37 over 1.28 days.<ref name=AAVSOtau>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5513 |title=Tau Canis Majoris |author =Watson, Christopher |date=4 January 2010 |work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=21 March 2014}}</ref> Its four main component stars are hot O-type stars, with a combined mass 80 times that of the Sun and shining with 500,000 times its luminosity, but little is known of their individual properties. A fifth component, a magnitude 10 star, lies at a distance of {{convert|13000|AU|ly|lk=on}}. The system is only 5&nbsp;million years old.<ref name=kalertau>{{cite web| first1=James B. | last1=Kaler | title=Tau Canis Majoris | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/taucma.html | access-date=22 March 2014}}</ref><!-- cites previous two sentences --> [[UW Canis Majoris]] is another Beta Lyrae-type star 3000 light-years from Earth; it is an [[eclipsing binary]] that ranges in magnitude from a minimum of 5.3 to a maximum of 4.8. It has a period of 4.4 days;{{sfn|Ridpath|Tirion|2001|pp=98–99}} its components are two massive hot blue stars, one a [[blue supergiant]] of spectral type O7.5–8 Iab, while its companion is a slightly cooler, less evolved and less luminous supergiant of spectral type O9.7Ib. The stars are 200,000 and 63,000 times as luminous as the Sun. However the fainter star is the more massive at 19 [[solar mass]]es to the primary's 16.<ref name="bagnuolo">{{Cite journal | last1 = Bagnuolo | first1 = William G. Jr. | last2 = Gies | first2 = Douglas R. | last3 = Hahula | first3 = Michael E. | last4 = Wiemker | first4 = Rafael | last5 = Wiggs | first5 = Michael S. | title = Tomographic Separation of Composite Spectra. 2: The Components of 29 UW Canis Majoris | doi = 10.1086/173822 | journal = The Astrophysical Journal | volume = 423 | pages = 446–55 | year = 1994 |bibcode = 1994ApJ...423..446B | doi-access = free }}</ref><!-- cites previous two sentences --> [[R Canis Majoris]] is another eclipsing binary that varies from magnitude 5.7 to 6.34 over 1.13 days,<ref name=AAVSOR>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=5154 |title=R Canis Majoris |author =Watson, Christopher |date=4 January 2010 |work=AAVSO Website|publisher=American Association of Variable Star Observers|access-date=18 February 2014}}</ref> with a third star orbiting these two every 93 years. The shortness of the orbital period and the low ratio between the two main components make this an unusual Algol-type system.<ref name=budding>{{cite journal|author1=Budding, E. |author2=Butland, R. |year=2011|title=Observations and Analysis of the System R Canis Majoris|journal=Monthly Notices of the Royal Astronomical Society|volume=418|issue=3|pages=1764–73|bibcode=2011MNRAS.418.1764B|doi = 10.1111/j.1365-2966.2011.19597.x |doi-access=free}}</ref>

Seven star systems have been found to have planets. [[Nu2 Canis Majoris|Nu<sup>2</sup> Canis Majoris]] is an ageing orange giant of spectral type K1III of apparent magnitude 3.91 located around 64 light-years distant.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=7+CMa |title = 7 Canis Majoris – Variable Star |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 26 February 2014}}</ref> Around 1.5 times as massive and 11 times as luminous as the Sun, it is orbited over a period of 763 days by a planet 2.6 times as massive as Jupiter.<ref name="Wittenmyer">{{cite journal | author=Wittenmyer | title= The Pan-Pacific Planet Search. I. A Giant Planet Orbiting 7 CMa | journal=[[Astrophysical Journal]] | volume=743 | issue=2 | year=2011 | pages=184–91 | doi=10.1088/0004-637X/743/2/184 | last2=Endl | first2=Michael | last3=Wang | first3=Liang | last4=Johnson | first4=John Asher | last5=Tinney | first5=C.G. | last6=O'Toole | first6=S.J. | bibcode=2011ApJ...743..184W|arxiv =  1111.1007| s2cid= 26948630 }}</ref> [[HD 47536]] is likewise an ageing orange giant found to have a planetary system—echoing the fate of the Solar System in a few billion years as the Sun ages and becomes a giant.<ref name="eso0305">{{cite press release | title=Distant World in Peril Discovered from La Silla: Giant Exoplanet Orbits Giant Star |work= ESO for the Public | date=22 January 2003 | publisher=[[European Southern Observatory]] | location=Garching, Germany | url=http://www.eso.org/public/news/eso0305/ | access-date=16 March 2014}}</ref> Conversely, [[HD 45364]] is a star 107 light-years distant that is a little smaller and cooler than the Sun, of spectral type G8V, which has two planets discovered in 2008. With orbital periods of 228 and 342 days, the planets have a 3:2 [[orbital resonance]], which helps stabilise the system.<ref name="Correia2009">{{cite journal | title=The HARPS Search for Southern Extra-solar Planets XVI. HD 45364, a Pair of Planets in a 3:2 Mean Motion Resonance | url=http://www.aanda.org/articles/aa/full_html/2009/11/aa10774-08/aa10774-08.html | last1=Correia | first1=A. C. M. | last2=Udry | first2=S. | last3=Mayor | first3=M. | last4=Benz | first4=W. | last5=Bertaux | first5=J.-L. | last6=Bouchy | first6=F. | last7=Laskar | first7=J. | last8=Lovis | first8=C. | last9=Mordasini | first9=C. | last10=Pepe | first10=F. | last11=Queloz | first11=D. | journal=Astronomy and Astrophysics | volume=496 | issue=2 | pages=521–26 | year=2009 | arxiv=0902.0597 | bibcode=2009A&A...496..521C | doi=10.1051/0004-6361:200810774 | s2cid=119235349 }}</ref> [[HD 47186]] is another sunlike star with two planets; the inner—[[HD 47186 b]]—takes four days to complete an orbit and has been classified as a [[Hot Neptune]], while the outer—[[HD 47186 c]]—has an eccentric 3.7-year period orbit and has a similar mass to [[Saturn]].<ref name="bouchy2009">{{cite journal |doi=10.1051/0004-6361:200810669 |title=The HARPS Search for Southern Extra-solar Planets. XVII. Super-Earth and Neptune-mass Planets in Multiple Planet Systems HD 47186 and HD 181433 |url=http://www.aanda.org/articles/aa/full_html/2009/11/aa10669-08/aa10669-08.html |last1=Bouchy |first1=François |last2=Mayor | first2=Michel |last3=Lovis |first3=Christophe |last4=Udry |first4=Stéphane |last5=Benz |first5=Willy |last6=Bertaux |first6=Jean-Loup |last7=Delfosse |first7=Xavier |last8=Mordasini |first8=Christoph |last9=Pepe |first9=Francesco |last10=Queloz |first10=Didier |last11=Ségransan |first11=Damien |journal=Astronomy and Astrophysics |volume=496 |issue=2 |pages=527–31 |year=2009 |arxiv=0812.1608 |bibcode=2009A&A...496..527B |s2cid=117778593 }}</ref> [[HD 43197]] is a sunlike star around 183 light-years distant that has two planets: a hot Jupiter-size planet with an eccentric orbit. The other planet, HD 43197 c, is another massive Jovian planet with a slightly oblong orbit outside of its habitable zone. <ref name="Naef2010">{{cite journal |doi=10.1051/0004-6361/200913616 |title=The HARPS Search for Southern Extrasolar Planets XXIII. 8 Planetary Companions to Low-activity Solar-type Stars |last1=Naef |first1=Dominique |last2=Mayor |first2=Michel |last3=Lo Curto |first3=Gaspare |last4=Bouchy |first4=François |last5=Lovis |first5=Christophe |last6=Moutou |first6=Claire |last7=Benz |first7=Willy |last8=Pepe |first8=Francesco |last9=Queloz |first9=Didier |last10=Santos |first10=Nuno C. |last11=Ségransan |first11=Damien |last12=Udry |first12=Stéphane |last13=Bonfils |first13=Xavier |last14=Delfosse |first14=Xavier |last15=Forveille |first15=Thierry |last16=Hébrard |first16=Guillaume |last17=Mordasini |first17=Christoph |last18=Perrier |first18=Christian |last19=Boisse |first19=Isabelle |last20=Sosnowska |first20=Danuta |journal=Astronomy and Astrophysics |volume=523 |page=A15 |year=2010 |arxiv=1008.4600 |bibcode=2010A&A...523A..15N |s2cid=118845989 |url=http://www.aanda.org/articles/aa/full_html/2010/15/aa13616-09/aa13616-09.html }}</ref>

[[Z Canis Majoris]] is a star system a mere 300,000 years old composed of two [[pre-main-sequence star]]s—a [[FU Orionis star]] and a [[Herbig Ae/Be star]],<ref name="szeifert">{{cite journal|author1=Szeifert, T. |author2=Hubrig, S. |author3=Schöller, M. |author4=Schütz, O. |author5=Stelzer, B. |author6=Mikulášek, Z. |year=2010|title=The Nature of the Recent Extreme Outburst of the Herbig Be/FU Orionis Binary Z Canis Majoris|journal=Astronomy and Astrophysics |volume=509|pages=L7 | bibcode=2010A&A...509L...7S|arxiv = 0912.3889 |doi = 10.1051/0004-6361/200913704 |s2cid=14928968 }}</ref> which has brightened episodically by two magnitudes to magnitude 8 in 1987, 2000, 2004 and 2008.<ref name="Whelan 2010">{{cite journal|author1=Whelan, E.T. |author2=Dougados, C. |author3=Perrin, M. D. |author4=Bonnefoy, M. |author5=Bains, I. |author6=Redman, M.P. |author7=Ray, T.P. |author8=Bouy, H. |author9=Benisty, M. |author10=Bouvier, J. |author11=Chauvin, G. |author12=Garcia, P.J.V. |author13=Grankvin, K. |author14=Malbet, F. |year=2010|title=The 2008 Outburst in the Young Stellar System Z CMa: The First Detection of Twin Jets|journal=The Astrophysical Journal Letters|volume=720|issue=1|pages=L119–24 |bibcode=2010ApJ...720L.119W|arxiv = 1008.0111 |doi = 10.1088/2041-8205/720/1/L119 |s2cid=119237775 }}</ref> The more massive Herbig Ae/Be star is enveloped in an irregular roughly spherical cocoon of dust that has an inner diameter of {{convert|20|AU|km|abbr=on}} and outer diameter of {{convert|50|AU|km|abbr=on}}. The cocoon has a hole in it through which light shines that covers an angle of 5 to 10 degrees of its circumference. Both stars are surrounded by a large envelope of in-falling material left over from the original cloud that formed the system. Both stars are emitting jets of material, that of the Herbig Ae/Be star being much larger—11.7 light-years long.<ref name="Canovas 2012">{{cite journal|author1=Canovas, H. |author2=Min, M. |author3=Jeffers, S.V. |author4=Rodenhuis, M. |author5=Keller, C.U. |year=2012|title=Constraining the Circumbinary envelope of Z Canis Majoris via Imaging Polarimetry|journal=Astronomy & Astrophysics|volume=543|issue=A70|pages=8 pp|bibcode=2012A&A...543A..70C|arxiv = 1205.3784 |doi = 10.1051/0004-6361/201117762 |s2cid=53690653 }}</ref> Meanwhile, [[FS Canis Majoris]] is another star with infra-red emissions indicating a compact shell of dust, but it appears to be a main-sequence star that has absorbed material from a companion. These stars are thought to be significant contributors to interstellar dust.<ref name="Miroshnichenko 2007">{{cite journal|author=Miroshnichenko, Anatoly S.|year=2007|title=Toward Understanding the B[e] Phenomenon. I. Definition of the Galactic FS CMa Stars|journal=The Astrophysical Journal|volume=667|issue=1|pages=497–504|bibcode=2007ApJ...667..497M|doi = 10.1086/520798 |citeseerx=10.1.1.548.81|s2cid=40320323 }}</ref>

=== Deep-sky objects ===
The band of the [[Milky Way]] goes through Canis Major, with only patchy obscurement by [[interstellar dust]] clouds. It is bright in the northeastern corner of the constellation, as well as in a triangular area between Adhara, Wezen and Aludra, with many stars visible in binoculars. Canis Major boasts several [[open cluster]]s.<ref name="crossen 2004">{{cite book|author1=Crossen, Craig |author2=Rhemann, Gerald |title=Sky Vistas: Astronomy for Binoculars and Richest-Field Telescopes|publisher=Springer|location=New York, New York|year=2004|pages=[https://archive.org/details/springer_10.1007-978-3-7091-0626-6/page/n139 113]–15|isbn=978-3-211-00851-5|url=https://archive.org/details/springer_10.1007-978-3-7091-0626-6|quote=Canis Major. }}</ref> The only [[Messier object]] is [[Messier 41|M41]] (NGC 2287), an open cluster with a combined [[visual magnitude]] of 4.5, around 2300 light-years from Earth. Located 4 degrees south of Sirius, it contains contrasting blue, yellow and orange stars and covers an area the apparent size of the [[full moon]]—in reality around 25 light-years in diameter.<ref name="kambic09">{{cite book|last=Kambic|first=Bojan |title=Viewing the Constellations with Binoculars: 250+ Wonderful Sky Objects to See and Explore|publisher=Springer|location=New York, New York|year=2009|pages=230–32|isbn=978-0-387-85355-0|url=https://books.google.com/books?id=3vxLNPNHOcwC&q=Sirius+%22M+41%22&pg=PA230}}</ref><!-- cites two previous sentences --> Its most luminous stars have already evolved into giants. The brightest is a 6.3-magnitude star of spectral type K3. Located in the field is [[12 Canis Majoris]], though this star is only 670 light-years distant.<ref>{{cite book|last=De Laet|first=Rony |title=The Casual Sky Observer's Guide: Stargazing with Binoculars and Small Telescopes|publisher=Springer|location=New York, New York|year=2011|pages=95–97|isbn=978-1-4614-0595-5|url=https://books.google.com/books?id=3fhBelJk-30C&pg=PA95}}</ref><!-- cites previous two sentences --> [[NGC 2360]], known as Caroline's Cluster after its discoverer [[Caroline Herschel]], is an open cluster located 3.5 degrees west of Muliphein and has a combined apparent magnitude of 7.2. Around 15 light-years in diameter, it is located 3700 light-years away from Earth,<ref name="o'meara">{{cite book |title=The Caldwell Objects |first=Stephen James |last=O'Meara |publisher=Cambridge University Press|location=Cambridge, United Kingdom |year=2002 |pages=231–33 | isbn=978-0-521-82796-6}}</ref> and has been dated to around 2.2&nbsp;billion years old.<ref name="Mermilliod">{{cite journal|author1=Mermilliod, Jean-Claude |author2=Mayor, Michel |year=1990|title= Red Giants in Open Clusters. III - Binarity and Stellar Evolution in Five Intermediate-age Clusters: NGC 2360, 2423, 5822, 6811, and IC 4756|journal=Astronomy and Astrophysics |volume=273|issue=1|pages= 61–72 |bibcode=1990A&A...237...61M}}</ref> [[NGC 2362]] is a small, compact open cluster, 5200 light-years from Earth. It contains about 60 stars, of which Tau Canis Majoris is the brightest member.{{sfn|Ridpath|Tirion|2001|pp=98–99}} Located around 3 degrees northeast of Wezen, it covers an area around 12 light-years in diameter, though the stars appear huddled around Tau when seen through binoculars. It is a very young open cluster as its member stars are only a few million years old.  Lying 2 degrees southwest of NGC 2362 is [[NGC 2354]] a fainter open cluster of magnitude 6.5, with around 15 member stars visible with binoculars.<ref name="kambic09"/><!-- cites previous three sentences --> Located around 30' northeast of NGC 2360,<ref>{{cite book|author=Thompson, Robert and Barbara|title=Illustrated Guide to Astronomical Wonders: From Novice to Master Observer|publisher=O'Reilly Media, Inc.|location=Sebastopol, California|year=2007|page=144|isbn=978-0-596-52685-6|url=https://books.google.com/books?id=ymt9nj_uPhwC&pg=PA144}}</ref> [[NGC 2359]] (Thor's Helmet or the Duck Nebula) is a relatively bright [[emission nebula]] in Canis Major, with an approximate magnitude of 10, which is 10,000 light-years from Earth. The nebula is shaped by [[HD 56925]], an unstable [[Wolf–Rayet star]] embedded within it.<ref>{{cite book |first = David H. |last = Levy |title = Deep Sky Objects |publisher = Prometheus Books |location = Amherst, New York |year = 2005 |isbn = 978-1-59102-361-6 |page = [https://archive.org/details/deepskyobjects00davi/page/108 108] |url = https://archive.org/details/deepskyobjects00davi/page/108 }}</ref>

[[File:Stars fleeing a cosmic crash.jpg|thumb|[[ESO 489-056]] is an irregular [[dwarf galaxy]], located 16 million light-years distant.<ref name="www.spacetelescope.org">{{cite news|title=Stars Fleeing a Cosmic Crash |url=http://www.spacetelescope.org/images/potw1332a/|access-date=14 August 2013|newspaper=ESA/Hubble Picture of the Week}}</ref> ]]

In 2003, an overdensity of stars in the region was announced to be the [[Canis Major Dwarf]], the closest [[satellite galaxy]] to Earth. However, there remains debate over whether it represents a disrupted dwarf galaxy or in fact a variation in the thin and thick disk and spiral arm populations of the Milky Way. Investigation of the area yielded only ten [[RR Lyrae variable]]s—consistent with the [[Milky Way halo|Milky Way's halo]] and thick disk populations rather than a separate dwarf spheroidal galaxy.<ref>{{cite journal|author1=Mateu, Cecilia |author2=Vivas, A. Katherina |author3=Zinn, Robert |author4=Miller, Lissa R. |author5=Abad, Carlos |year=2009|title=No Excess of RR Lyrae Stars in the Canis Major Overdensity|journal=The Astronomical Journal|volume=37|issue=5|pages=4412–23 |bibcode=2009AJ....137.4412M|doi=10.1088/0004-6256/137/5/4412|arxiv = 0903.0376 |s2cid=18967866 }}</ref> On the other hand, a [[globular cluster]] in Puppis, [[NGC 2298]]—which appears to be part of the Canis Major dwarf system—is extremely metal-poor, suggesting it did not arise from the Milky Way's thick disk, and instead is of extragalactic origin.<ref>{{cite book  | last = O'Meara  | first = Stephen James  | year = 2011  | title = Deep-Sky Companions: The Secret Deep | publisher = Cambridge University Press | location = Cambridge, United Kingdom  | isbn = 978-0-521-19876-9 |url=https://books.google.com/books?id=v859bKO0A4gC&q=Canis+Major&pg=PA140 |page=139}}</ref>

[[NGC 2207 and IC 2163]] are a pair of face-on [[interacting galaxy|interacting]] spiral galaxies located 125&nbsp;million light-years from Earth. About 40&nbsp;million years ago, the two galaxies had a close encounter and are now moving farther apart; nevertheless, the smaller IC 2163 will eventually be incorporated into NGC 2207. As the interaction continues, gas and dust will be perturbed, sparking extensive [[star formation]] in both galaxies.{{sfn|Wilkins|Dunn|2006|p=456}} Supernovae have been observed in NGC 2207 in 1975 (type Ia [[SN 1975a]]),<ref>{{cite journal|author1=Kirshner, Robert P. |author2=Arp, H.C. |author3=Dunlap, J.R. |year=1976|title=Observations of Supernovae – 1975a in NGC 2207 and 1975b in the Perseus Cluster|journal=Astrophysical Journal|volume=207|issue=1|pages=44–52|bibcode=1976ApJ...207...44K|doi=10.1086/154465|doi-access=free}}</ref> 1999 (the type Ib [[SN 1999ec]]),<ref>{{cite journal|author1=Jha, S. |author2=Garnavich, P. |author3=Challis, P. |author4=Kirshner, R. |author5=Berlind, P. |year=1999|title=Supernova 1999ec in NGC 2207|journal=IAU Circular|volume=7269|page=2|bibcode=1999IAUC.7269....2J}}</ref> 2003 (type 1b supernova [[SN 2003H]]),<ref>{{cite web | first=David | last=Bishop | title=Bright Supernovae – 2003 | publisher=Rochester University | url=http://www.rochesterastronomy.org/sn2003/ | access-date=7 March 2014}}</ref> and 2013 (type II supernova [[SN 2013ai]]).<ref>{{cite journal |last1=Alain |first1=Klotz |last2=E. |first2=Conseil |last3=M. |first3=Fraser |last4=Joseph |first4=Brimacombe |last5=C. |first5=Inserra |last6=N. |first6=Walton |last7=N. |first7=Blagorodnova |last8=M. |first8=Nicholl |last9=S. |first9=Benetti |last10=A. |first10=Pastorello |last11=S. |first11=Valenti |last12=S. |first12=Taubenberger |last13=J. |first13=Smartt S. |last14=K. |first14=Smith |last15=D. |first15=Young |last16=M. |first16=Sullivan |last17=A. |first17=Gal-Yam |last18=O. |first18=Yaron |title=Supernova 2013ai in NGC 2207 = Psn J06161835-2122329 |journal=Central Bureau Electronic Telegrams |date=2013 |volume=3431 |pages=1 |bibcode=2013CBET.3431....1K}}</ref> Located 16&nbsp;million light-years distant,<ref name="www.spacetelescope.org"/> [[ESO 489-056]] is an irregular [[dwarf galaxy|dwarf-]] and [[low-surface-brightness galaxy]] that has one of the lowest [[metallicity|metallicities]] known.<ref>{{cite journal|author1=Kunth, Daniel |author2=Östlin, Goran |date=2000|title=The Most Metal-poor Galaxies|journal=The Astronomy and Astrophysics Review|volume=10|issue=1–2|pages=1–79|bibcode=2000A&ARv..10....1K|doi=10.1007/s001590000005|arxiv = astro-ph/9911094 |s2cid=15487742 }}</ref>

{{Clear}}

== References ==
===Citations===
{{Reflist}}

=== Bibliography ===
* {{cite book
  |last=Allen
  |first=Richard Hinckley
  |title=Star Names: Their Lore and Meaning
  |year=1963
  |orig-year=1899
  |publisher=Dover
  |location=New York, New York
  |isbn=((978-0-486-21079-7))
  |url=https://archive.org/details/starnamestheirlo00alle
  }}
* {{cite book
  | title = The Morning Star Rises: An Account of Polynesian Astronomy
  | last = Makemson
  | first = Maud Worcester
  | year = 1941
  | publisher = Yale University Press
  | location = New Haven, Connecticut
  | bibcode = 1941msra.book.....M
 }}
* {{cite book
  | last1 = Ridpath
  | first1 = Ian
  | last2 = Tirion
  | first2 = Wil
  | year = 2001
  | title = Stars and Planets Guide
  | publisher = Princeton University Press
  | location = Princeton, New Jersey
  | isbn = 978-0-691-08913-3
  }}
* {{Cite book
  | title = Uranographie Chinoise
  | last = Schlegel
  | first = Gustaaf
  | publisher = Ch'eng Wen Publishing Company
  | location = Taipei, Republic of China
  | year = 1967
  | orig-year = 1875
  | language = fr
  }}
* {{cite book
  | last = Wagman
  | first = Morton
  | year = 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
  }}
* {{cite book
  | first1 = Jamie
  | last1 = Wilkins
  | first2 = Robert
  | last2 = Dunn
  | year = 2006
  | title = 300 Astronomical Objects: A Visual Reference to the Universe
  | publisher = Firefly Books
  | location = Buffalo, New York
  | isbn = 978-1-55407-175-3
  }}

== External links ==
{{Commons}}
{{EB1911 poster|Canis Major}}
* [http://www.allthesky.com/constellations/canismajor/ The Deep Photographic Guide to the Constellations: Canis Major]
* [http://astrojan.nhely.hu/canisma.htm The clickable Canis Major]
* [https://iconographic.warburg.sas.ac.uk/category/vpc-taxonomy-017643 Warburg Institute Iconographic Database (medieval and early modern images of Canis Major)]

{{Stars of Canis Major}}
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[[Category:Canis Major| ]]
[[Category:Constellations listed by Ptolemy]]
[[Category:Southern constellations]]