Editing Canis Minor

{{Short description|Constellation in the northern celestial hemisphere}}
{{Featured article}}
{{Use dmy dates|date=June 2021}}
{{Use British English|date=January 2013}}
{{Infobox constellation
| name = Canis Minor
| abbreviation = CMi
| genitive = Canis Minoris
| pronounce = {{IPAc-en|ˌ|k|eɪ|n|ᵻ|s|_|ˈ|m|aɪ|n|ər}} {{respell|KAY|niss|_|MY|nər}}, genitive {{IPAc-en|ˌ|k|eɪ|n|ᵻ|s|_|m|ᵻ|ˈ|n|ɔr|ᵻ|s}} {{respell|KAY|niss|_|min|OR|iss}}
| symbolism = The Lesser Dog
| RA = {{RA|07|06.4}} to {{RA|08|11.4}}<ref name="boundary"/>
| dec = {{dec|13.22}} to {{dec|−0.36}}<ref name="boundary"/>
| areatotal = 183
| arearank = 71st
| numbermainstars = 2
| numberbfstars = 14
| numberstarsplanets = 1
| numberbrightstars = 2
| numbernearbystars = 4
| brighteststarname = [[Procyon]] (α CMi)
| starmagnitude = 0.34
| neareststarname = [[Procyon]] (α CMi)
| stardistancely = 11.41
| stardistancepc = 3.50
| numbermessierobjects = 0
| meteorshowers = [[Canis-Minorids]]
| bordering =
  {{plainlist |
* [[Monoceros]]
* [[Gemini (constellation)|Gemini]]
* [[Cancer (constellation)|Cancer]]
* [[Hydra (constellation)|Hydra]]
 }}
| latmax = [[north pole|90]]
| latmin = [[75th parallel south|75]]
| month = February
| notes =
}}

'''Canis Minor''' is a small [[constellation]] in the [[Celestial sphere|northern celestial hemisphere]]. In the second century, it was included as an [[Asterism (astronomy)|asterism]], or pattern, of two stars in [[Ptolemy]]'s 48 constellations, and it is counted among the [[Lists of constellations|88 modern constellations]]. Its name is [[Latin]] for "lesser dog", in contrast to [[Canis Major]], the "greater dog"; both figures are commonly represented as following the constellation of [[Orion (constellation)|Orion]] the hunter.

Canis Minor contains only two stars brighter than the fourth [[apparent magnitude|magnitude]], [[Procyon]] (Alpha Canis Minoris), with a magnitude of 0.34, and [[Gomeisa]] (Beta Canis Minoris), with a magnitude of 2.9. The constellation's dimmer stars were noted by [[Johann Bayer]], who named eight stars including Alpha and Beta, and [[John Flamsteed]], who numbered fourteen. Procyon is the [[List of brightest stars|eighth-brightest star]] in the night sky, as well as one of the [[List of nearest stars|closest]]. A yellow-white [[main-sequence]] star, it has a [[white dwarf]] [[Binary star|companion]]. Gomeisa is a blue-white main-sequence star. [[Luyten's Star]] is a ninth-magnitude [[red dwarf]] and the [[Solar System]]'s next closest stellar neighbour in the constellation after Procyon. Additionally, Procyon and Luyten's Star are only 1.12 light-years away from each other,<ref name=AnnotLHS33>{{cite web|title= Annotations on LHS&nbsp;33 object|work= [[SIMBAD]]|publisher=[[Centre de Données astronomiques de Strasbourg]]|url=http://cdsannotations.u-strasbg.fr/annotations/simbadObject/971564|access-date=2022-02-23}}</ref> and Procyon would be the brightest star in Luyten's Star's sky. The fourth-magnitude [[HD 66141]], which has evolved into an orange [[giant star|giant]] towards the end of its [[stellar evolution|life cycle]], was discovered to have a planet in 2012. There are two faint [[deep-sky object]]s within the constellation's borders. The 11 [[Canis-Minorids]] are a [[meteor shower]] that can be seen in early December.

== History and mythology ==
[[File:Cmi.jpg|thumb|left|Canis Minor, as depicted by [[Johann Bode]] in his 1801 work ''Uranographia'']]
Though strongly associated with the [[Classical Greece|Classical Greek]] [[celestial cartography|uranographic]] tradition, Canis Minor originates from ancient [[Mesopotamia]]. Procyon and Gomeisa were called ''MASH.TAB.BA'' or "twins" in the ''[[Three Stars Each]]'' tablets, dating to around 1100 BC. In the later ''[[MUL.APIN]]'', this name was also applied to the pairs of [[Pi3 Orionis|Pi<sup>3</sup>]] and [[Pi4 Orionis|Pi<sup>4</sup> Orionis]] and [[Zeta Geminorum|Zeta]] and [[Xi Orionis]]. The meaning of ''MASH.TAB.BA'' evolved as well, becoming the twin deities [[Lulal]] and [[Latarak]], who are on the opposite side of the sky from ''[[Papsukkal]]'', the True Shepherd of Heaven in [[Babylonian mythology]]. Canis Minor was also given the name ''DAR.LUGAL'', its position defined as "the star which stands behind it [Orion]", in the ''MUL.APIN''; the constellation represents a [[rooster]]. This name may have also referred to the constellation [[Lepus (constellation)|Lepus]].<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 | pages=9–28 | bibcode=1998JBAA..108....9R }}</ref> ''DAR.LUGAL'' was also denoted ''DAR.MUŠEN'' and ''DAR.LUGAL.MUŠEN'' in Babylonia. Canis Minor was then called ''tarlugallu'' in [[Akkadian astronomy]].<ref>{{cite journal |title = Astral Magic in Babylonia |journal = Transactions of the American Philosophical Society |series=New Series |volume = 85 |issue = 4 |year = 1995 |last = Reiner |first = Erica |authorlink = Erica Reiner |pages = i–150 |jstor = 1006642|doi =10.2307/1006642 }}</ref>

Canis Minor was one of the original 48 constellations formulated by [[Ptolemy]] in his second-century [[Almagest]], in which it was defined as a specific pattern ([[Asterism (astronomy)|asterism]]) of stars; Ptolemy identified only two stars and hence no depiction was possible.<ref name="allen"/> The [[Ancient Greek]]s called the constellation προκυων/''Procyon'', "coming before the dog", transliterated into [[Latin]] as ''Antecanis'', ''Praecanis'', or variations thereof, by Cicero and others. Roman writers also appended the descriptors ''parvus'', ''minor'' or ''minusculus'' ("small" or "lesser", for its faintness), ''septentrionalis'' ("northerly", for its position in relation to Canis Major), ''primus'' (rising "first") or ''sinister'' (rising to the "left") to its name ''Canis''.<ref name="allen">{{cite book | last=Allen | first=Richard Hinckley | year=1963 | orig-year=1899 | title=Star Names: Their Lore and Meaning | edition=corrected | publisher=Dover Publications | location=Mineola, New York | isbn = ((978-0-486-21079-7)) | page=[https://archive.org/details/starnamestheirlo00alle/page/383 383] | url=https://archive.org/details/starnamestheirlo00alle| url-access=registration }}</ref>
In [[Greek mythology]], Canis Minor was sometimes connected with the [[Teumessian fox|Teumessian Fox]], a beast turned into stone with its hunter, [[Laelaps (mythology)|Laelaps]], by [[Zeus]], who placed them in heaven as Canis Major (Laelaps) and Canis Minor (Teumessian Fox).<ref>Apollodorus, Bibliotheca 3,192.</ref><ref>{{cite book |url = https://books.google.com/books?id=yMbzhPrIkt4C&pg=PA275 |title = Nature Guide Stars and Planets |page = 275 |author = DK Publishing |publisher = Penguin |year = 2012 |isbn = 978-1-4654-0353-7}}</ref> [[Eratosthenes]] accompanied the Little Dog with Orion, while [[De astronomia|Hyginus]] linked the constellation with [[Maera (hound)|Maera]], a dog owned by [[Icarius of Athens]].<ref>{{cite book|last=Klepešta|first=Josef|author2=Rükl, Antonín|title=Constellations|publisher=Hamlyn|location=London, England|year=1974|orig-year=1969|pages=[https://archive.org/details/constellationsco0000klep/page/118 118–19]|isbn=978-0-600-00893-4|url=https://archive.org/details/constellationsco0000klep/page/118}}</ref><ref name="ridpath star tales"/> On discovering the latter's death, the dog and Icarius' daughter [[Erigone (daughter of Icarius)|Erigone]] took their lives and all three were placed in the sky—Erigone as [[Virgo (constellation)|Virgo]] and Icarius as [[Boötes]].<ref name="ridpath star tales">{{cite web |last=Ridpath |first=Ian |authorlink=Ian Ridpath |title=Canis Minor |url=http://www.ianridpath.com/startales/canisminor.html |access-date=26 May 2012 |work=Star Tales}}</ref> As a reward for his faithfulness, the dog was placed along the "banks" of the Milky Way, which the ancients believed to be a heavenly river, where he would never suffer from thirst.<ref>Mark R. Chartrand III (1982) Skyguide: A Field Guide for Amateur Astronomers, p. 126 ({{ISBN|0-307-13667-1}}).</ref>

The [[astronomy in medieval Islam|medieval Arabic astronomers]] maintained the depiction of Canis Minor (''al-Kalb al-Asghar'' in [[Arabic]]) as a dog; in his [[Book of the Fixed Stars]], [[Abd al-Rahman al-Sufi]] included a diagram of the constellation with a canine figure superimposed.<ref name=upton>{{cite journal |pages =  179–197 [195–96] |title = A Manuscript of "The Book of the Fixed Stars" by ʿAbd Ar-Raḥmān Aṣ-Ṣūfī |first = Joseph M. |last = Upton |journal = Metropolitan Museum Studies |volume = 4 |issue = 2 |date = March 1933 | jstor = 1522800 |doi =  10.2307/1522800}}</ref><ref>{{cite journal |pages =  1–26 [Plate 12] |first = Emmy |last = Wellesz |title = An Early al-Ṣūfī Manuscript in the Bodleian Library in Oxford: A Study in Islamic Constellation Images |journal = Ars Orientalis |year = 1959 |volume = 3 |jstor = 4629096 }}</ref> There was one slight difference between the Ptolemaic vision of Canis Minor and the Arabic; al-Sufi claims [[Mirzam]], now assigned to [[Orion (constellation)|Orion]], as part of both Canis Minor—the collar of the dog—and its modern home. The Arabic names for both Procyon and Gomeisa alluded to their proximity and resemblance to Sirius, though they were not direct translations of the Greek; Procyon was called ''ash-Shi'ra ash-Shamiya'', the "Syrian Sirius" and Gomeisa was called ''ash-Shira al-Ghamisa'', the Sirius with bleary eyes.<ref name=upton/> 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 Minor and Canis Major 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>

The ancient Egyptians thought of this constellation as [[Anubis]], the jackal god.<ref>Chartrand, p. 126.</ref>
[[File:Sidney Hall - Urania's Mirror - Monoceros, Canis Minor, and Atelier Typographique.jpg|thumb|400px|The constellation Canis Minor can be seen alongside [[Monoceros]] and the obsolete constellation [[Atelier Typographique]] in this 1825 star chart from ''[[Urania's Mirror]]''.]]
Alternative names have been proposed: [[Johann Bayer]] in the early 17th century termed the constellation ''Fovea'' "The Pit", and ''Morus'' "[[Sycamine]] Tree". Seventeenth-century German poet and author [[Philipp von Zesen|Philippus Caesius]] linked it to the dog of Tobias from the [[Biblical apocrypha|Apocrypha]].<ref name="allen"/> [[Richard A. Proctor]] gave the constellation the name ''Felis'' "the Cat" in 1870 (contrasting with Canis Major, which he had abbreviated to ''Canis'' "the Dog"),<ref name="allen"/> explaining that he sought to shorten the constellation names to make them more manageable on [[celestial charts]].<ref>{{cite book | last = Proctor | first = Richard Anthony | authorlink = Richard A. Proctor | year = 1870 | title = A Star Atlas for the Library, the School and the Observatory | publisher = Longmans, Green | location = London, England | url = https://books.google.com/books?id=yzRRAAAAYAAJ&pg=PA17 | pages=16–17}}</ref> Occasionally, Canis Minor is confused with Canis Major and given the name ''Canis Orionis'' ("Orion's Dog").<ref>{{cite book |page = 137 |title = Outer Space : Myths, Name Meanings, Calendars from the Emergence of History to the Present Day |last1 = Jobes |first1 = Gertrude |last2 = Jobes |first2 = James |year = 1964 |publisher = Scarecrow Press|location=New York, New York|oclc=882705}}</ref>

=== In non-Western astronomy ===

In [[Chinese astronomy]], the stars corresponding to Canis Minor lie in the [[Vermilion Bird of the South]] (南方朱雀, ''Nán Fāng Zhū Què''). Procyon, Gomeisa and Eta Canis Minoris form an asterism known as Nánhé, the Southern River.<ref name="ridpath star tales"/><ref>{{cite web |author1 = 陳冠中 |author2 = 陳輝樺 |url = http://aeea.nmns.edu.tw/2006/0607/ap060716.html |publisher = AEEA (Activities of Exhibition and Education in Astronomy) |script-title = zh:天文教育資訊網 |date = 16 July 2006 |language = zh |access-date = 20 December 2010 |archive-date = 22 August 2011 |archive-url = https://web.archive.org/web/20110822132833/http://aeea.nmns.edu.tw/2006/0607/ap060716.html |url-status = dead }}</ref> With its counterpart, the Northern River Beihe ([[Castor (star)|Castor]] and [[Pollux (star)|Pollux]]), Nánhé was also associated with a gate or sentry. Along with [[Zeta Cancri|Zeta]] and [[8 Cancri]], [[6 Canis Minoris]] and [[11 Canis Minoris]] formed the asterism ''Shuiwei'', which literally means "water level". Combined with additional stars in [[Gemini (constellation)|Gemini]], Shuiwei represented an official who managed floodwaters or a marker of the water level.<ref name="ridpath star tales"/> Neighboring Korea recognized four stars in Canis Minor as part of a different constellation, "the position of the water". This constellation was located in the Red Bird, the southern portion of the sky.<ref>{{cite journal |title = A Korean Star Map |last1 = Rufus |first1 = W. Karl |last2 = Chao |first2 = Celia |pages = 316–26 |journal = Isis |volume = 35 |issue = 4 |date = Autumn 1944 |jstor = 330843 |doi = 10.1086/358723|s2cid = 144879973 }}</ref>

[[Polynesian people]]s often did not recognize Canis Minor as a constellation, but they saw Procyon as significant and often named it; in the [[Tuamotu Archipelago]] it was known as ''Hiro'', meaning "twist as a thread of coconut fiber", and ''Kopu-nui-o-Hiro'' ("great paunch of Hiro"), which was either a name for the modern figure of Canis Minor or an alternative name for Procyon. Other names included ''Vena'' (after a [[goddess]]), on [[Mangaia]] and ''Puanga-hori'' (false ''Puanga'', the name for [[Rigel]]), in [[New Zealand]]. In the [[Society Islands]], Procyon was called ''Ana-tahua-vahine-o-toa-te-manava'', literally "Aster the priestess of brave heart", figuratively the "pillar for elocution".<ref>{{cite book| last = Makemson | first = Maud Worcester | year = 1941 | publisher = Yale University Press | location = New Haven, Connecticut | title = The Morning Star Rises: An Account of Polynesian Astronomy | pages = 199, 209, 247, 267, 280| bibcode = 1941msra.book.....M }}</ref><ref>{{cite journal |title = Tahitian Astronomy: Birth of the Heavenly Bodies |last = Henry |first = Teuira |authorlink=Teuira Henry|journal = The Journal of the Polynesian Society |volume = 16 |issue = 2 |pages= 101–04 |date = June 1907 | jstor = 20700813}}</ref> The [[Wardaman people]] of the [[Northern Territory]] in Australia gave Procyon and Gomeisa the names ''Magum'' and ''Gurumana'', describing them as humans who were transformed into [[gum trees]] in [[the Dreaming]]. Although their skin had turned to bark, they were able to speak with a human voice by rustling their leaves.<ref name="darksparklers">{{cite book|last=Harney|first=Bill Yidumduma |author2=Cairns, Hugh C.|title=Dark Sparklers|publisher=Hugh C. Cairns|location=Merimbula, New South Wales|year=2004|orig-year=2003|edition=Revised|page=142|isbn=978-0-9750908-0-0}}</ref>

The [[Aztec calendar]] was related to [[Aztec astronomy|their cosmology]]. The stars of Canis Minor were incorporated along with some stars of Orion and Gemini into an asterism associated with the day called "Water".<ref>{{cite journal |title = Calendar Animals and Deities |last = Kelley |first = David H. |pages = 317–337 [333] |journal = Southwestern Journal of Anthropology |volume = 16 |issue = 3 |date = Autumn 1960 |doi = 10.1086/soutjanth.16.3.3629035 |jstor = 3629035|s2cid = 131473640 }}</ref>

== Characteristics ==
Lying directly south of Gemini's bright stars [[Castor (star)|Castor]] and [[Pollux (star)|Pollux]],<ref name="sky">{{cite book|last=Newell|first=W.J.|title=The Australian Sky|publisher=Jacaranda Press|location=Brisbane, Queensland |year=1970|orig-year=1965|page=53 | isbn = 978-0-7016-0037-2 |oclc = 7053675}} (invalid isbn)</ref> Canis Minor is a small constellation bordered by [[Monoceros]] to the south, Gemini to the north, [[Cancer (constellation)|Cancer]] to the northeast, and [[Hydra (constellation)|Hydra]] to the east. It does not border [[Canis Major]]; Monoceros is in between the two. Covering 183 square degrees, Canis Minor ranks seventy-first of the 88 constellations in size. It appears prominently in the southern sky during the [[Northern Hemisphere]]'s winter.<ref name="garfinkle1997">{{cite book | first=Robert A. |last=Garfinkle | title=Star-hopping: Your Visa to Viewing the Universe | publisher=Cambridge University Press|location=Cambridge, England | year=1997 | pages=78–81 | isbn = 978-0-521-59889-7 }}</ref> The constellation boundaries, as set by Belgian astronomer [[Eugène Delporte]] in 1930, are defined by a polygon of 14 sides. In the [[equatorial coordinate system]], the [[right ascension]] coordinates of these borders lie between {{RA|07|06.4}} and {{RA|08|11.4}}, while the [[declination]] coordinates are between {{dec|13.22}} and {{dec|−0.36}}.<ref name="boundary">{{cite journal | title=Canis Minor, Constellation Boundary | journal=The Constellations | url=https://www.iau.org/public/themes/constellations/#cmi | access-date=25 May 2012 }}</ref> Most visible in the evening sky from January to March,<ref>{{cite book |last1=Ellyard |first1=David |url=https://books.google.com/books?id=5Gn0ivM4EK0C&pg=PA4 |title=The Southern Sky Guide |last2=Tirion |first2=Wil |publisher=Cambridge University Press |year=2008 |isbn=978-0-521-71405-1 |edition=3rd |location=Port Melbourne, Victoria |page=4 |authorlink2=Wil Tirion |orig-year=1993}}</ref> Canis Minor is most prominent at 10 p.m. during mid-February.<ref>{{cite book |title = The Monthly Sky Guide |last1 = Ridpath |first1 = Ian |last2 = Tirion |first2 = Wil |date = 13 November 2006 |edition = 7th |publisher = Cambridge University Press |location = Cambridge, England |pages = 21–22 |isbn = 978-0-521-68435-4}}</ref> It is then seen earlier in the evening until July, when it is only visible after sunset before setting itself, and rising in the morning sky before dawn.<ref>{{cite web|url=http://rasnz.org.nz/Stars/Canis.htm|title=Canis Major and Canis Minor, 2 Constellations for February|last=Rodmell|first=Paul|publisher=Royal Astronomical Society of New Zealand|access-date=17 January 2013|url-status=dead|archive-url=https://web.archive.org/web/20130114221231/http://www.rasnz.org.nz/Stars/Canis.htm|archive-date=14 January 2013}}</ref> The constellation's three-letter abbreviation, as adopted by the [[International Astronomical Union]] in 1922, is "CMi".<ref name="pa30_469">{{cite journal | last=Russell | first=Henry Norris |authorlink = Henry Norris Russell | 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>

== Features ==
=== Stars ===
{{See also|List of stars in Canis Minor}}
[[Image:CanisMinorCC.jpg|thumb|right|300px|The constellation Canis Minor as it can be seen by the naked eye]]
Canis Minor contains only two stars brighter than fourth [[apparent magnitude|magnitude]]. At magnitude 0.34,<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=CCDM%20J07393%2B0514%20A |title = Procyon AB – Spectroscopic Binary |publisher = SIMBAD | access-date = 8 January 2013}}</ref> Procyon, or Alpha Canis Minoris, is the [[List of brightest stars|eighth-brightest star]] in the night sky, as well as one of the [[List of nearest stars|closest]]. Its name means "before the dog" or "preceding the dog" in Greek, as it rises an hour before the "Dog Star", [[Sirius]], of Canis Major. It is a [[binary star]] system, consisting of a yellow-white [[main-sequence]] star<ref name="ridpath">{{cite book |last1=Ridpath |first1=Ian |title=Stars and Planets Guide |last2=Tirion |first2=Wil |publisher=Princeton University Press |year=2001 |isbn=978-0-691-08913-3 |location=Princeton, New Jersey |pages=100–01 }}</ref> of [[spectral type]] F5&nbsp;IV-V, named Procyon&nbsp;A, and a faint [[white dwarf]] companion of spectral type DA, named Procyon&nbsp;B. Procyon&nbsp;B, which orbits the more massive star every 41 years, is of magnitude 10.7.<ref name="ridpath"/> Procyon&nbsp;A is 1.4 times the [[Sun's mass]], while its smaller companion is 0.6 times as massive as the Sun.<ref name=aj131>{{cite journal | last1=Gatewood | first1=George | last2=Han | first2=Inwoo | title=An Astrometric Study of Procyon | journal=Astronomical Journal | volume=131 | issue=2 | pages=1015–21 | year=2006 | doi=10.1086/498894 | bibcode=2006AJ....131.1015G | doi-access=free }}</ref> The system is {{convert|11.4|ly|pc|abbr=off|lk=on}} from [[Earth]], the shortest distance to a northern-hemisphere star of the first magnitude.<ref name="ridpath"/><ref>{{cite book |title = The Cambridge Encyclopedia of Stars |page = 63 |last = Kaler |first = James B. |authorlink=James B. Kaler |publisher = Cambridge University Press |year = 2006|location = Cambridge, England |isbn = 978-0-521-81803-2}}</ref> [[Gomeisa]], or Beta Canis Minoris, with a magnitude of 2.89, is the second-brightest star in Canis Minor. Lying {{convert|160 ± 10|ly|pc|abbr=off|lk=off}} from the [[Solar System]],<ref name=Gaia-DR2beta>{{cite DR2|3143264535611161088}}</ref> it is a blue-white main-sequence star of [[spectral class]] B8&nbsp;Ve.<ref name=betvar>{{cite web |url = https://www.aavso.org/vsx/index.php?view=detail.top&oid=5638 |title = Bet CMi |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 13 January 2013 |date = 4 January 2010}}</ref> Although fainter to Earth observers, it is much brighter than Procyon, and is 250 times as [[Luminosity#Astronomy|luminous]] and three times as massive as the Sun.<ref name=Kalerbeta>{{Cite journal | first1=Jim | last1=Kaler | journal=Stars | title=Gomeisa (Beta Canis Minoris) | url=http://stars.astro.illinois.edu/sow/gomeisa.html | access-date=27 January 2012 }}</ref> Although its variations are slight, Gomeisa is classified as a [[shell star]] (Gamma Cassiopeiae variable), with a maximum magnitude of 2.84 and a minimum magnitude of 2.92.<ref name=betvar/> It is surrounded by a disk of gas which it heats and causes to emit radiation.<ref name=Kalerbeta/>

Johann Bayer used the Greek letters Alpha to Eta to label the most prominent eight stars in the constellation, designating two stars as Delta (named Delta<sup>1</sup> and Delta<sup>2</sup>).{{sfn|Wagman|2003|pp=76–77}} [[John Flamsteed]] numbered fourteen stars, discerning a third star he named Delta<sup>3</sup>;{{sfn|Wagman|2003|p=77}} his star 12 Canis Minoris was not found subsequently.{{sfn|Wagman|2003|p=369}} In Bayer's 1603 work ''[[Uranometria]]'', Procyon is located on the dog's belly, and Gomeisa on its neck.{{sfn|Wagman|2003|p=504}} [[Gamma Canis Minoris|Gamma]], [[Epsilon Canis Minoris|Epsilon]] and [[Eta Canis Minoris]] lie nearby,<ref name="kambic"/> marking the dog's neck, crown and chest, respectively.{{sfn|Wagman|2003|p=504}} Although it has an apparent magnitude of 4.34, Gamma Canis Minoris is an orange [[stellar classification|K-type]] [[giant star|giant]] of spectral class K3-III C, which lies {{convert|318|ly|pc|abbr=off|lk=off}} away.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Gamma+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Gamma Canis Minoris |publisher = SIMBAD | access-date = 25 May 2012}}</ref> Its colour is obvious when seen through binoculars.<ref name="kambic">{{cite book|last=Kambič|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|page=32 | isbn = 978-0-387-85354-3 |url=https://books.google.com/books?id=3vxLNPNHOcwC&pg=PA233}}</ref> It is a multiple system, consisting of the [[spectroscopic binary]] Gamma A and three optical companions, Gamma B, magnitude 13; Gamma C, magnitude 12; and Gamma D, magnitude 10. The two components of Gamma A orbit each other every 389.2 days, with an eccentric orbit that takes their separation between 2.3 and 1.4 [[astronomical unit]]s (AU).<ref>{{cite web |url = http://stars.astro.illinois.edu/sow/gammacmi.html |title = Gamma Canis Minoris |last = Kaler |first = Jim |work = Star of the Week |access-date = 29 January 2013 |date = 19 March 2010}}</ref> Epsilon Canis Minoris is a yellow [[bright giant]] of spectral class G6.5IIb of magnitude of 4.99.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Epsilon+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Epsilon Canis Minoris |publisher = SIMBAD | access-date = 25 May 2012}}</ref> It lies {{convert|730|-|810|ly|pc|abbr=off|lk=off}} from Earth,<ref name=Gaia-DR2eps>{{cite DR2|3155451625572457344}}</ref> with 13 times the diameter and 750 times the luminosity of the Sun.<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=108–12|url=https://books.google.com/books?id=KcIg02TKW6QC&pg=PA110}}</ref> Eta Canis Minoris is a giant of spectral class F0III of magnitude 5.24,<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Eta+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Eta Canis Minoris |publisher = SIMBAD | access-date = 25 May 2012}}</ref> which has a yellowish hue when viewed through binoculars as well as a faint companion of magnitude 11.1.<ref name="garfinkle1997"/><ref>{{cite book |last1=Malin |first1=David |url=https://books.google.com/books?id=EQAYGmZT0o8C&pg=PA183 |title=Hartung's Astronomical Objects for Southern Telescopes: A Handbook for Amateur Observers |last2=Frew |first2=David J. |publisher=Cambridge University Press |year=1995 |isbn=978-0-521-55491-6 |location=Cambridge, England |page=184}}</ref> Located 4 [[arcsecond]]s from the primary, the companion star is actually around 440 AU from the main star and takes around 5,000 years to orbit it.<ref name="kalereta">{{cite web|url=http://stars.astro.illinois.edu/sow/etacmi.html|title=Eta and Delta-1 CMi |last=Kaler|first=Jim|work=Stars|publisher=University of Illinois|access-date=22 August 2012}}</ref>

Near Procyon, three stars share the name [[Delta Canis Minoris]]. [[Delta1 Canis Minoris|Delta<sup>1</sup>]] is a yellow-white [[stellar classification|F-type]] giant of magnitude 5.25 located around {{convert|790|ly|pc|abbr=off|lk=off}} from Earth. About 360 times as luminous and 3.75 times as massive as the Sun, it is expanding and cooling as it ages, having spent much of its life as a [[B-type main-sequence star|main sequence star]] of spectrum B6V.<ref name="kalereta"/> Also known as 8 Canis Minoris, [[Delta2 Canis Minoris|Delta<sup>2</sup>]] is an [[F-type main-sequence star]] of spectral type F2V and magnitude 5.59 which is {{convert|136|ly|pc|abbr=off|lk=off}} distant.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=8+CMi |title = 8 Canis Minoris |publisher = SIMBAD | access-date = 13 January 2013}}</ref> The last of the trio, [[Delta3 Canis Minoris|Delta<sup>3</sup>]] (also known as 9 Canis Minoris), is a [[white main sequence star]] of spectral type A0Vnn and magnitude 5.83 which is {{convert|680 |ly|pc|abbr=off|lk=off}} distant.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=9+CMi |title = 9 Canis Minoris |publisher = SIMBAD | access-date = 13 January 2013}}</ref> These stars mark the paws of the Lesser Dog's left hind leg, while magnitude 5.13 [[Zeta Canis Minoris|Zeta]] marks the right.{{sfn|Wagman|2003|p=504}}<ref name=simbadzeta/> A blue-white [[bright giant]] of spectral type B8II, Zeta lies around {{convert|623|ly|pc|abbr=off|lk=off}} away from the Solar System.<ref name=simbadzeta>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Zeta+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Zeta Canis Minoris |publisher = SIMBAD | access-date = 6 September 2012}}</ref>

Lying 222 ± 7 light-years away with an apparent magnitude of 4.39,<ref name=Gaia-DR2lam>{{cite DR2|3087964941887693056}}</ref><ref name="exoplanet">{{cite encyclopedia|url=https://exoplanet.eu/catalog/hd_66141_b--1222/|title = Planet HD 66141 b|last=Zolotukhin|first=Ivan|year=2012|encyclopedia=[[Extrasolar Planets Encyclopaedia]]|access-date=21 December 2012}}</ref> [[HD 66141]] is 6.8&nbsp;billion years old and has [[Stellar evolution#Mid-sized stars|evolved]] into an orange giant of spectral type K2III with a diameter around 22 times that of the Sun, and weighing 1.1 solar masses. It is 174 times as luminous as the Sun, with an [[absolute magnitude]] of −0.15.<ref name="Lee">{{Cite journal |title=Detection of an Exoplanet Around the Evolved K Giant HD 66141 |arxiv=1211.2054 |year=2012|journal=Astronomy & Astrophysics|volume=548|doi=10.1051/0004-6361/201118014 |author1=Lee, B.-C. |author2=Mkrtichian, D. E. |author3=Han, I. |author4=Park, M.-G. |author5=Kim, K.-M. |pages=A118|bibcode = 2012A&A...548A.118L |s2cid=54984721 }}</ref> HD 66141 was mistakenly named 13 Puppis, as its celestial coordinates were recorded incorrectly when catalogued and hence mistakenly thought to be in the constellation of [[Puppis]]; Bode gave it the name Lambda Canis Minoris, which is now obsolete.{{sfn|Wagman|2003|p=460}} The orange giant is orbited by a planet, [[HD 66141b]], which was detected in 2012 by measuring the star's [[radial velocity]]. The planet has a mass around 6 times that of [[Jupiter]] and a [[orbital period|period]] of 480 days.<ref name="exoplanet"/>

A [[red giant]] of spectral type M4III, [[BC Canis Minoris]] lies around {{convert|500|ly|pc|abbr=off|lk=off}} distant from the Solar System.<ref name="Tabur">{{cite journal | title=Long-term Photometry and Periods for 261 Nearby Pulsating M Giants | last1=Tabur |first1 =V. |last2=Bedding |first2=T. R. |year=2009 |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume= 400 | issue =4 |pages= 1945–61 |doi=10.1111/j.1365-2966.2009.15588.x | last3=Kiss | first3=L. L. | last4=Moon | first4=T. T. | last5=Szeidl | first5=B. | last6=Kjeldsen | first6=H. | doi-access=free |arxiv = 0908.3228 |bibcode = 2009MNRAS.400.1945T | s2cid=15358380 }}</ref> It is a [[semiregular variable star]] that varies between a maximum magnitude of 6.14 and minimum magnitude of 6.42.<ref>{{cite web |url = https://www.aavso.org/vsx/index.php?view=detail.top&oid=5595 |title = BC CMi |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 13 January 2013 |date = 25 August 2009}}</ref> Periods of 27.7, 143.3 and 208.3 days have been recorded in its pulsations.<ref name="Tabur"/> [[AZ Canis Minoris|AZ]], [[AD Canis Minoris|AD]] and [[BI Canis Minoris]] are [[Delta Scuti variable]]s—short period (six hours at most) pulsating stars that have been used as [[standard candles]] and as subjects to study [[astroseismology]].<ref>{{cite web|url=https://www.aavso.org/vsots_delsct|title=Delta Scuti and the Delta Scuti Variables|last=Templeton|first=Matthew |date=16 July 2010|work=Variable Star of the Season|publisher=AAVSO (American Association of Variable Star Observers)|access-date=3 November 2012}}</ref> AZ is of spectral type A5IV,<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=AZ+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = V* AZ Canis Minoris – Variable of Delta Scuti type |publisher = SIMBAD | access-date = 1 October 2012}}</ref> and ranges between magnitudes 6.44 and 6.51 over a period of 2.3 hours.<ref>{{cite web |url = https://www.aavso.org/vsx/index.php?view=detail.top&oid=5593 |title = AZ CMi |publisher = AAVSO |work = International Variable Star Index |access-date = 14 January 2013 |date = 4 January 2010}}</ref> AD has a spectral type of F2III,<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=AD+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = V* AD Canis Minoris – Variable of Delta Scuti type |publisher = SIMBAD | access-date = 1 October 2012}}</ref> and has a maximum magnitude of 9.21 and minimum of 9.51, with a period of approximately 2.95 hours.<ref>{{cite web |url = https://www.aavso.org/vsx/index.php?view=detail.top&oid=5572 |title = AD Canis Minoris |publisher = AAVSO |work = International Variable Star Index |access-date = 17 January 2013 |date = 4 January 2010}}</ref> BI is of spectral type F2 with an apparent magnitude varying around 9.19<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=BI+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = V* BI Canis Minoris – Variable of Delta Scuti type |publisher = SIMBAD | access-date = 1 October 2012}}</ref> and a period of approximately 2.91 hours.<ref>{{cite web |url = https://www.aavso.org/vsx/index.php?view=detail.top&oid=5601 |title = BI Canis Minoris |publisher = AAVSO |work = International Variable Star Index |access-date = 17 January 2013 |date = 2 February 2011}}</ref>

At least three red giants are [[Mira variable]]s in Canis Minor. [[S Canis Minoris]], of spectral type M7e,<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=S+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = S Canis Minoris |publisher = SIMBAD | access-date = 27 August 2012}}</ref> is the brightest, ranging from magnitude 6.6 to 13.2 over a period of 332.94 days.<ref name="garfinkle1997"/><ref>{{cite web |url = https://www.aavso.org/vsx/index.php?view=detail.top&oid=5516 |title = S CMi |publisher = AAVSO |work = International Variable Star Index |access-date = 14 January 2013 |date = 4 January 2010}}</ref> [[V Canis Minoris]] ranges from magnitude 7.4 to 15.1 over a period of 366.1 days. Similar in magnitude is [[R Canis Minoris]], which has a maximum of 7.3, but a significantly brighter minimum of 11.6. An [[S-type star]], it has a period of 337.8 days.<ref>{{cite book |title = Patrick Moore's Data Book of Astronomy |last1 = Moore |first1 = Patrick |authorlink1 = Patrick Moore |last2 = Rees |first2 = Robin |page=396 |isbn = 978-0-521-89935-2 |publisher = Cambridge University Press |year = 2011}}</ref>

[[YZ Canis Minoris]] is a [[red dwarf]] of spectral type M4.5V and magnitude 11.2,<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=YZ+Canis+Minoris&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = V* YZ Canis Minoris – Variable of BY Draconis Type |publisher = SIMBAD | access-date = 1 October 2012}}</ref> roughly three times the size of Jupiter and {{convert|20|ly|pc|abbr=off|lk=off}} from Earth. It is a [[flare star]], emitting unpredictable outbursts of energy for mere minutes, which might be much more powerful analogues of [[solar flare]]s.<ref name="First flares">{{cite journal|title=First Flares on a Distant Star|journal=New Scientist|date=4 February 1982 |page=305|url=https://books.google.com/books?id=XQwcxTIERmUC&pg=PA305}}</ref> [[Luyten's Star]] (GJ 273) is a red dwarf star of spectral type M3.5V and close neighbour of the Solar System. Its visual magnitude of 9.9 renders it too faint to be seen with the naked eye,<ref name="RECONS">{{cite web|title=The One Hundred Nearest Stars |date=1 January 2012 |publisher=Georgia State University Astronomy |url=http://www.chara.gsu.edu/RECONS/TOP100.posted.htm |access-date=1 October 2012 |location=Atlanta, Georgia |url-status=dead |archive-url=https://web.archive.org/web/20120513202710/http://www.chara.gsu.edu/RECONS/TOP100.posted.htm |archive-date=13 May 2012 }}</ref> even though it is only {{convert|12.39|ly|pc|abbr=off}} away.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=GJ+273&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = LHS 33 – High Proper-motion Star |publisher = SIMBAD | access-date = 5 October 2012}}</ref> Fainter still is [[PSS 544-7]], an eighteenth-magnitude red dwarf around 20 per cent the mass of the Sun, located {{convert|685|ly|pc|abbr=off|lk=off}} from Earth. First noticed in 1991, it is thought to be a cannonball star, shot out of a star cluster and now moving rapidly through space directly away from the [[galactic disc]].<ref>{{cite journal |first1=Carlos |last1=de la Fuente Marcos |last2=de la Fuente Marcos |first2=Raúl |title=A Cannonball Star Candidate in Canis Minor |journal=New Astronomy |volume=10 |issue=7 |pages=551–59 |doi=10.1016/j.newast.2005.04.001 |year=2005 |bibcode = 2005NewA...10..551D }}</ref>

The [[WZ Sagittae]]-type [[dwarf nova]] [[DY Canis Minoris]] (also known as [[VSX J074727.6+065050]]) flared up to magnitude 11.4 over January and February 2008 before dropping eight magnitudes to around 19.5 over approximately 80 days. It is a remote binary star system where a white dwarf and low-mass star orbit each other close enough for the former star to draw material off the latter and form an [[accretion disc]]. This material builds up until it erupts dramatically.<ref>{{cite journal|author1=Shears, Jeremy |author2=Brady, Steve |author3=Bolt, Greg |author4=Campbell, Tut |author5=Collins, Donald F. |author6=Cook, Lewis M. |author7=Crawford, Timothy R. |author8=Koff, Robert |author9=Krajci, Tom |author10=McCormick, Jennie |author11=Nelson, Peter |author12=Patterson, Joseph |author13=Ponthière, Pierre de |author14=Potter, Mike |author15=Rea, Robert |author16=Roberts, George |author17=Sabo, Richard |author18=Staels, Bart |author19=Vanmunster, Tonny |year=2009|title=VSX J074727.6+065050: A New WZ Sagittae Star in Canis Minor |journal=Journal of the British Astronomical Association|volume=119|issue=6|pages=340–46 |arxiv = 0905.0061 |bibcode = 2009JBAA..119..340S }}</ref>

=== Deep-sky objects ===
[[File:Red and Long Dead Abell 24.tif|thumb|Nebula [[Abell 24]]<ref>{{cite web |title=Red and Long Dead |url=https://www.eso.org/public/images/potw1927a/ |website=eso.org |access-date=8 July 2019 |language=en}}</ref>]]
The [[Milky Way]] passes through much of Canis Minor, yet it has few [[deep-sky object]]s.<ref name="inglis">{{cite book|last=Inglis|first=Mike|title=Astronomy of the Milky Way: Observer's Guide to the Southern Sky|publisher=Springer|location=New York, New York|year=2004|page=20|isbn=978-1-85233-742-1|url=https://books.google.com/books?id=1r0qvMjSCGAC&pg=SA2-PA9}}</ref> [[William Herschel]] recorded four objects in his 1786 work ''[[Catalogue of Nebulae and Clusters of Stars]]'', including two he mistakenly believed were star clusters.<ref name=bratton>{{cite book|last=Bratton|first=Mark |title=The Complete Guide to the Herschel Objects: Sir William Herschel's Star Clusters, Nebulae and Galaxies|publisher=Cambridge University Press|location = Cambridge, England | year=2011|page=134 | isbn = 978-0-521-76892-4 |url=https://books.google.com/books?id=JLuv9bAUbBwC&pg=PA134}}</ref> [[NGC 2459]] is a group of five thirteenth- and fourteenth-magnitude stars that appear to lie close together in the sky but are not related.<ref>{{cite web|url=http://cseligman.com/text/atlas/ngc24a.htm#2459 |title=NGC Objects: NGC 2450 – 2499 |work= Celestial Atlas|author=Seligman, Courtney |access-date=25 May 2012}}</ref> A similar situation has occurred with [[NGC 2394]], also in Canis Minor.<ref>{{cite web|url=http://cseligman.com/text/atlas/ngc23a.htm#2394 |title=NGC Objects: NGC 2350 – 2399 |work= Celestial Atlas|author=Seligman, Courtney|access-date=25 May 2012}}</ref> This is a collection of fifteen unrelated stars of ninth magnitude and fainter.<ref name=bratton/>

Herschel also observed three faint galaxies, two of which are interacting with each other.<ref name=bratton/> [[NGC 2508]] is a [[lenticular galaxy]] of thirteenth magnitude, estimated at 205 million light-years' distance (63 million parsecs) with a diameter of {{Convert|80000|ly|pc|abbr=off}}.<ref>{{cite web|url=http://cseligman.com/text/atlas/ngc25.htm#2508 |title=NGC Objects: NGC 2500 – 2549 |work= Celestial Atlas|author=Seligman, Courtney|access-date=25 May 2012}}</ref> Named as a single object by Herschel, [[NGC 2402]] is actually a pair of near-adjacent galaxies that appear to be interacting with each other. Only of fourteenth and fifteenth magnitudes, respectively, the elliptical and spiral galaxy are thought to be approximately 245&nbsp;million light-years distant, and each measure 55,000 light-years in diameter.<ref>{{cite web|url=http://cseligman.com/text/atlas/ngc24.htm#2402 |title=NGC Objects: NGC 2400 – 2449 |work= Celestial Atlas|author=Seligman, Courtney|access-date=25 May 2012}}</ref>

===Meteor showers===
The 11 Canis-Minorids, also called the Beta Canis Minorids,<ref>{{cite book |last = Jenniskens |first = Peter |title = Meteor Showers and Their Parent Comets|pages=200, 769 |publisher = Cambridge University Press |year = 2006 |isbn = 978-0-521-85349-1}}</ref> are a [[meteor shower]] that arise near the fifth-magnitude star [[11 Canis Minoris]] and were discovered in 1964 by Keith Hindley, who investigated their [[trajectory]] and proposed a common origin with the comet [[D/1917 F1]] Mellish.<ref>{{Cite journal | last1 = Hindley | first1 = K. B. | last2 = Houlden | first2 = M. A. | doi = 10.1038/2251232a0 | title = The 11 Canis Minorids—A New Meteor Stream Probably Associated with Comet Mellish 1917 I | journal = Nature | volume = 225 | issue = 5239 | pages = 1232–33 | year = 1970 | pmid =  16057004|bibcode = 1970Natur.225.1232H | s2cid = 4170596 }}</ref> However, this conclusion has been refuted subsequently as the number of orbits analysed was low and their trajectories too disparate to confirm a link.<ref>{{cite journal |title = Meteor Showers of Comet C/1917 F1 Mellish |first1 = P. |last1 = Vereš |first2 = L. |last2 = Kornoš |first3 = J. |last3 = Tóth |year = 2011 |journal = Monthly Notices of the Royal Astronomical Society |arxiv = 1010.5733|bibcode = 2011MNRAS.412..511V |doi = 10.1111/j.1365-2966.2010.17923.x |volume=412 |issue = 1 |pages=511–521|doi-access = free |s2cid = 119297606 }}</ref> They last from 4 to 15 December, peaking over 10 and 11 December.<ref>{{cite book|last=Levy|first=David H.|authorlink=David H. Levy|title=David Levy's Guide to Observing Meteor Showers|publisher=Cambridge University Press|location = Cambridge, England|year=2007|page=122 | isbn = 978-0-521-69691-3|url=https://books.google.com/books?id=jAr7HMnlPGUC&pg=PA122}}</ref>

== References ==
{{Reflist}}

==Sources==
* {{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|VA]]
 | isbn = 978-0-939923-78-6
 }}

== External links ==
{{Commons and category|Canis Minor|Canis_Minor}}
* [http://www.allthesky.com/constellations/monoceros/ The Deep Photographic Guide to the Constellations: Canis Minor]
* [https://iconographic.warburg.sas.ac.uk/category/vpc-taxonomy-017645 Warburg Institute Iconographic Database (medieval and early modern images of Canis Minor)]

{{Stars of Canis Minor}}
{{Constellations}}
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[[Category:Canis Minor| ]]
[[Category:Constellations listed by Ptolemy]]
[[Category:Equatorial constellations]]
[[Category:Constellations]]