Editing Carina (constellation) (section)

== Notable features ==
[[Image:Constellation Carina.jpg|thumb|left|256px|The constellation Carina as it can be seen by the naked eye]]

=== Stars ===
{{See also|List of stars in Carina}}

Carina contains [[Canopus]], a white-hued [[supergiant]] that is the second-brightest [[star]] in the night sky at magnitude −0.72. Alpha Carinae, as Canopus is formally designated, is 313 [[light-year]]s from Earth. Its traditional name comes from the mythological [[Canopus (mythology)|Canopus]], who was a navigator for [[Menelaus]], king of Sparta.{{sfn|Ridpath|Tirion|2001|pp=104–106}}

There are several other stars above magnitude 3 in Carina. [[Beta Carinae]], traditionally called Miaplacidus, is a blue-white-hued star of magnitude 1.7, 111 light-years from Earth. [[Epsilon Carinae]] is an orange-hued giant star similarly bright to Miaplacidus at magnitude 1.9; it is 630 light-years from Earth. Another fairly bright star is the blue-white-hued [[Theta Carinae]]; it is a magnitude 2.7 star 440 light-years from Earth. Theta Carinae is also the most prominent member of the cluster [[IC 2602]]. [[Iota Carinae]] is a white-hued supergiant star of magnitude 2.2, 690 light-years from Earth.{{sfn|Ridpath|Tirion|2001|pp=104–106}}

[[Eta Carinae]] is the most prominent [[variable star]] in Carina, with a mass of approximately 100 [[solar mass]]es and 4 million times as bright as the Sun.{{sfn|Ridpath|Tirion|2001|pp=104–106}} It was first discovered to be unusual in 1677, when its magnitude suddenly rose to 4, attracting the attention of [[Edmond Halley]].{{sfn|Levy|2005|p=101}} Eta Carinae is inside NGC 3372, commonly called the [[Carina Nebula]].{{sfn|Ridpath|Tirion|2001|pp=104–106}} It had a long outburst in 1827, when it brightened to magnitude 1, only fading to magnitude 1.5 in 1828. Its most prominent outburst made Eta Carinae the equal of [[Sirius]]; it brightened to magnitude −1.5 in 1843. In the decades following 1843 it appeared relatively placid, having a magnitude between 6.5 and 7.9.{{sfn|Levy|2005|p=101}} However, in 1998, it brightened again, though only to magnitude 5.0, a far less drastic outburst. Eta Carinae is a [[binary star]], with a companion that has a period of 5.5 years; the two stars are surrounded by the [[Homunculus Nebula]], which is composed of gas that was ejected in 1843.{{sfn|Ridpath|Tirion|2001|pp=104–106}}

There are several less prominent variable stars in Carina. [[HD 84810|l Carinae]] is a [[Cepheid variable]] noted for its brightness; it is the brightest Cepheid that is variable to the unaided eye. It is a yellow-hued supergiant star with a minimum magnitude of 4.2 and a maximum magnitude of 3.3; it has a period of 35.5 days.{{sfn|Ridpath|Tirion|2001|pp=104–106}}

[[V382 Carinae]] is a [[yellow hypergiant]], one of the rarest types of stars. It is a [[slow irregular variable]], with a minimum magnitude of 4.05 and a maximum magnitude of 3.77.<ref>{{Cite web |title=VSX : Detail for V0382 Car |url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=6135 |access-date=2024-07-29 |website=www.aavso.org}}</ref> As a hypergiant, V382 Carinae is a luminous star, with 212,000 times more luminosity than the Sun and over 480 times the Sun's size.<ref name="cepheids">{{cite journal |last1=Groenewegen |first1=M. A. T. |year=2020 |title=Analysing the spectral energy distributions of Galactic classical Cepheids |journal=[[Astronomy and Astrophysics]] |volume=635 |pages=A33 |arxiv=2002.02186 |bibcode=2020A&A...635A..33G |doi=10.1051/0004-6361/201937060 |s2cid=211043995}}</ref>

Two bright [[Mira variable]] stars are in Carina: [[R Carinae]] and [[S Carinae]]; both stars are [[red giant]]s. R Carinae has a minimum magnitude of 10.0 and a maximum magnitude of 4.0. Its period is 309 days and it is 416 light-years from Earth. S Carinae is similar, with a minimum magnitude of 10.0 and a maximum magnitude of 5.0. However, S Carinae has a shorter period—150 days, though it is much more distant at 1,300 light-years from Earth.{{sfn|Ridpath|Tirion|2001|pp=104–106}}

Carina is home to several [[double star]]s and [[binary star]]s. [[Upsilon Carinae]] is a binary star with two blue-white-hued giant components, 1,600 light-years from Earth. The primary is of magnitude 3.0 and the secondary is of magnitude 6.0; the two components are distinguishable in a small amateur telescope.{{sfn|Ridpath|Tirion|2001|pp=104–106}}
[[File:Diamond cross.png|thumb|The Diamond Cross as highlighted in the constellation of Carina.]]
Two asterisms are prominent in Carina. The 'Diamond Cross' is composed of the stars [[Beta Carinae|Beta]], [[Theta Carinae|Theta]], [[Upsilon Carinae|Upsilon]] and [[Omega Carinae]].<ref>{{cite web |title=Diamond Cross |url=https://www.constellation-guide.com/diamond-cross/ |website=Constellation Guide |access-date=11 April 2023}}</ref> The Diamond Cross is visible south of 20ºN [[latitude]], and is larger but fainter than the Southern Cross in [[Crux]]. Flanking the Diamond Cross is the [[False cross]], composed of four stars{{sfn|Ridpath|Tirion|2001|pp=104–106}} - two stars in Carina, [[Iota Carinae]] and [[Epsilon Carinae]], and two stars in Vela, [[Kappa Velorum]] and [[Delta Velorum|Delta Velorum{{sfn|Ridpath|Tirion|2001|pp=104–106}}]] - and is often mistaken for the Southern Cross, causing errors in [[Celestial navigation|astronavigation]].

=== Deep-sky objects ===
Carina is known for its [[Carina Nebula|namesake nebula]], NGC 3372,{{sfn|Levy|2005|p=100}} discovered by French astronomer [[Nicolas-Louis de Lacaille]] in 1751, which contains several [[nebula]]e. The Carina Nebula overall is an extended [[emission nebula]] approximately 8,000 light-years away and 300 light-years wide that includes vast [[star formation|star-forming regions]].{{sfn|Wilkins|Dunn|2006|p={{page needed|date=July 2012}}}} It has an overall magnitude of 8.0{{sfn|Levy|2005|p=101}} and an apparent diameter of over 2 degrees.{{sfn|Ridpath|Tirion|2001|pp=104–106}} Its central region is called the Keyhole, or the [[Keyhole Nebula]]. This was described in 1847 by [[John Herschel]], and likened to a keyhole by Emma Converse in 1873.<ref name=appletons>{{cite book|title=Appletons' Journal|url=https://books.google.com/books?id=BgMZAAAAYAAJ&pg=PA818|year=1873|publisher=[[D. Appleton and Company]]|pages=818–}}</ref> The Keyhole is about seven light-years wide and is composed mostly of [[ionized hydrogen]], with two major star-forming regions. The [[Homunculus Nebula]] is a [[planetary nebula]] visible to the naked eye that is being ejected by the erratic [[luminous blue variable]] star [[Eta Carinae]], the most massive visible star known. Eta Carinae is so massive that it has reached the theoretical upper limit for the mass of a star and is therefore unstable. It is known for its outbursts; in 1840 it briefly became one of the brightest stars in the sky due to a particularly massive outburst, which largely created the Homunculus Nebula. Because of this instability and history of outbursts, Eta Carinae is considered a prime [[supernova]] candidate for the next several hundred thousand years because it has reached the end of its estimated million-year life span.{{sfn|Wilkins|Dunn|2006|p={{page needed|date=July 2012}}}}

[[NGC 2516]] is an open cluster that is both quite large<ref name=":0">{{Cite book |last=Chartrand |first=Mark R |title=National Audubon Society Field Guide to the Night Sky |publisher=Alfred A. Knopf, Inc. |year=1991 |isbn=0-679-40852-5 |location=New York, USA |pages=470}}</ref> (approximately half a degree square) and bright, visible to the unaided eye.<ref name=":0" /> It is located 1,100 light-years from Earth and has approximately 80 stars, the brightest of which is a [[red giant]] star of magnitude 5.2. [[NGC 3114]] is another open cluster approximately of the same size, though it is more distant at 3,000 light-years from Earth. It is more loose and dim than NGC 2516, as its brightest stars are only 6th magnitude. The most prominent open cluster in Carina is [[IC 2602]], also called the "Southern [[Pleiades]]". It contains [[Theta Carinae]], along with several other stars visible to the unaided eye. In total, the cluster possesses approximately 60 stars. The Southern Pleiades is particularly large for an open cluster, with a diameter of approximately one degree. Like IC 2602, [[NGC 3532]] is visible to the unaided eye<ref name=":0" /> and is of comparable size. It possesses approximately 150 stars that are arranged in an unusual shape, approximating an [[ellipse]] with a dark central area. Several prominent orange giants are among the cluster's bright stars, of the 7th magnitude. Superimposed on the cluster is [[Chi Carinae]], a yellow-white-hued star of magnitude 3.9, far more distant than NGC 3532.{{sfn|Ridpath|Tirion|2001|pp=104–106}}

Carina also contains the naked-eye [[globular cluster]] [[NGC 2808]].<ref name=":0" /> [[Epsilon Carinae]] and [[Upsilon Carinae]] are double stars visible in small telescopes.

One noted [[galaxy cluster]] is 1E 0657-56, the [[Bullet Cluster]]. At a distance of 4 billion light-years ([[redshift]] 0.296), this galaxy cluster is named for the [[bow shock|shock wave]] seen in the [[intracluster medium]], which resembles the shock wave of a supersonic bullet. The bow shock visible is thought to be due to the smaller galaxy cluster moving through the intracluster medium at a relative speed of 3,000–4,000 kilometers per second to the larger cluster. Because this [[gravitational interaction]] has been ongoing for hundreds of millions of years, the smaller cluster is being destroyed and will eventually merge with the larger cluster.{{sfn|Wilkins|Dunn|2006|p={{page needed|date=July 2012}}}}

=== Meteors ===
Carina contains the radiant of the [[Eta Carinids]] meteor shower, which peaks around January 21 each year.