Template:Short description Template:Use dmy dates Template:Infobox nebula Template:Sky

The Carina Nebula<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> or Eta Carinae Nebula<ref>Uranometria 2000.0</ref> (catalogued as NGC 3372; also known as the Great Carina Nebula<ref>APOD, Picture of the day for 27 Dec 2018</ref>) is a large, complex area of bright and dark nebulosity in the constellation Carina, located in the Carina–Sagittarius Arm of the Milky Way galaxy. The nebula is approximately Template:Convert from Earth.<ref name="kuhn19" />

The nebula has within its boundaries the large Carina OB1 association and several related open clusters, including numerous O-type stars and several Wolf–Rayet stars. Template:Nowrap encompasses the star clusters Template:Nowrap and Template:Nowrap. Template:Nowrap is one of the youngest known star clusters at half a million years old and contains stars like the O2 supergiant Template:Nowrap. Template:Nowrap is the home of many extremely luminous stars, such as Template:Nowrap and the Eta Carinae star system. Template:Nowrap, Template:Nowrap, Template:Nowrap, Template:Nowrap, and Template:Nowrap are also considered members of the association. Template:Nowrap is the oldest and furthest from Template:Nowrap, indicating sequential and ongoing star formation.

The nebula is one of the largest diffuse nebulae in our skies. Although it is four times as large as and even brighter than the famous Orion Nebula, the Carina Nebula is much less well known due to its location in the southern sky. It was discovered by Nicolas-Louis de Lacaille in 1752 from the Cape of Good Hope.

The Carina Nebula was selected as one of five cosmic objects observed by the James Webb Space Telescope, as part of the release of its first official science images. A detailed image was made of an early star-forming region of NGC 3324 known as the Cosmic Cliffs.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Discovery and basic informationEdit

Nicolas-Louis de Lacaille discovered the nebula on 25 January 1752.<ref name="messier.seds.org" /><ref name=Jones_1969>Template:Cite journal</ref> Its dimensions are 120×120 arcminutes centered on the coordinates of right ascension Template:RA and declination Template:DEC.<ref name="ngcic3372" /> In modern times it is calculated to be around Template:Convert from Earth.<ref name="kuhn19" />

Objects within the Carina NebulaEdit

Eta CarinaeEdit

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File:Etacarxirvis.png
Eta Carinae observed in different wavelengths

Eta Carinae is a highly luminous hypergiant star. Estimates of its mass range from 100 to 150 times the mass of the Sun, and its luminosity is about four million times that of the Sun.

This object is currently the most massive star that can be studied in great detail, because of its location and size. Several other known stars may be more luminous and more massive, but data on them is far less robust. (Caveat: Since examples such as the Pistol Star have been demoted by improved data, one should be skeptical of most available lists of "most massive stars". In 2006, Eta Carinae still had the highest confirmed luminosity, based on data across a broad range of wavelengths.) Stars with more than 80 times the mass of the Sun produce more than a million times as much light as the Sun. They are quite rare—only a few dozen in a galaxy as big as ours—and they flirt with disaster near the Eddington limit, i.e., the outward pressure of their radiation is almost strong enough to counteract gravity. Stars that are more than 120 solar masses exceed the theoretical Eddington limit, and their gravity is barely strong enough to hold in its radiation and gas, resulting in a possible supernova or hypernova in the near future.

Eta Carinae's effects on the nebula can be seen directly. Dark globules and some other less visible objects have tails pointing directly away from the massive star. The entire nebula would have looked very different before the Great Eruption in the 1840s surrounded Eta Carinae with dust, drastically reducing the amount of ultraviolet light it put into the nebula.

Homunculus NebulaEdit

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File:Eta Carinae 1.jpg
Eta Carinae, surrounded by the Homunculus Nebula

Within the large bright nebula is a much smaller feature, immediately surrounding Eta Carinae itself, known as the Homunculus Nebula (from Latin meaning Little Man). It is believed to have been ejected in an enormous outburst in 1841 which briefly made Eta Carinae the second-brightest star in the sky.

The Homunculus Nebula is a small H II region, with gas shocked into ionized and excited states.<ref name="teodoro2008">Template:Cite journal</ref> It also absorbs much of the light from the extremely luminous central stellar system and re-radiates it as infrared (IR). It is the brightest object in the sky at mid-IR wavelengths.<ref name="Davidson2012">Template:Cite book</ref>Template:Rp

The distance to the Homunculus can be derived from its observed angular dimensions and calculated linear size, assuming it is axially symmetric. The most accurate distance obtained using this method is Template:Convert. The largest radius of the bipolar lobes in this model is about 22,000 AU, and the axis is oriented 41° from the line of sight, or 49° relative to the plane of the sky, which means it is seen from Earth slightly more "end on" than "side on".<ref name="smith2006apj">Template:Cite journal</ref>

Keyhole NebulaEdit

File:Keyhole in the Carina Nebula (eso0905a crop).jpg
The Keyhole Nebula is a dark nebulosity superimposed on the brightest part of the Carina Nebula.

The Keyhole, or Keyhole Nebula, is a small dark cloud of cold molecules and dust within the Carina Nebula, containing bright filaments of hot, fluorescing gas, silhouetted against the much brighter background nebula. John Herschel used the term "lemniscate-oval vacuity" when first describing it,<ref name="herschel1847">Template:Cite book</ref> and subsequently referred to it simply as the "oval vacuity".<ref name="herschel1864">Template:Cite journal</ref> The term lemniscate continued to be used to describe this portion of the nebula<ref name="abbott1973">Template:Cite journal</ref> until popular astronomy writer Emma Converse described the shape of the nebula as "resembling a keyhole" in an 1873 Appleton's Journal article.<ref name="appletons1873">Template:Cite journal</ref> The name Keyhole Nebula then came into common use, sometimes for the Keyhole itself, sometimes to describe the whole of the Carina Nebula (signifying "the nebula that contains the Keyhole").<ref name="Moore1914">Template:Cite journal</ref><ref>See, e.g., Template:Cite book</ref>

The diameter of the Keyhole structure is approximately Template:Convert. Its appearance has changed significantly since it was first observed, possibly due to changes in the ionizing radiation from Eta Carinae.<ref name="Walborn1977">Template:Cite journal</ref> The Keyhole does not have its own NGC designation. It is sometimes erroneously called NGC 3324,<ref>For example, see APOD – NGC 3324.</ref> but that catalogue designation refers to a reflection and emission nebula just northwest of the Carina Nebula (or to its embedded star cluster).<ref name="Cooper2008">Template:Cite book</ref><ref name="ngcic3324">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="simbad3324">Template:Cite simbad</ref>

Defiant FingerEdit

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File:"Finger of God" Bok globule in the Carina Nebula.jpg
Hubble image of the Defiant Finger. North is down.

A small Bok globule in the Keyhole Nebula (at RA 10hTemplate:Nbsp44mTemplate:Nbsp30s, Dec −59°Template:Nbsp40') has been photographed by the Hubble Space Telescope and is nicknamed the "Carina Defiant Finger" due to its shape.<ref>Template:Cite simbad</ref> In Hubble images, light can be seen radiating off the edges of the globule; this is especially visible in the southern tip, where the "finger" is. It is thought that the Defiant Finger is being ionized by the bright Wolf–Rayet star WR 25, and/or Trumpler 16-244, a bright blue supergiant. It has a mass of at least Template:Solar mass, and stars may be forming within it. Like other interstellar clouds under intense radiation, the Defiant Finger will eventually be completely evaporated; for this cloud the time frame is predicted to be 200,000 to 1,000,000 years.<ref name=Smith2004>Template:Cite journal</ref>

Trumpler 14Edit

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File:Trumpler 14 by Hubble.jpg
Hubble image of the open cluster Trumpler 14

Trumpler 14 is an open cluster with a diameter of Template:Convert, located within the inner regions of the Carina Nebula, approximately Template:Convert from Earth.<ref name="Dias2014">Template:Cite journal</ref> It is one of the main clusters of the Template:Nowrap stellar association, which is the largest association in the Carina Nebula.<ref name="Davidson2012" /> About 2,000 stars have been identified in Template:Nowrap.<ref name="sciencedaily2009">Template:Cite journal</ref> and the total mass of the cluster is estimated to be Template:Solar mass.<ref name="Sana2010">Template:Cite journal</ref>

Trumpler 15Edit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Trumpler 15 is a star cluster on the north-east edge of the Carina Nebula. Early studies disagreed about the distance, but astrometric measurements by the Gaia mission have confirmed that it is the same distance as the rest of Carina OB1.<ref name="kuhn19" />

Trumpler 16Edit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} Trumpler 16 is one of the main clusters of the Carina OB1 stellar association, which is the largest association in the Carina Nebula, and it is bigger and more massive than Template:Nowrap.<ref name="Davidson2012" /> The star Eta Carinae is part of this cluster.

Mystic MountainEdit

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Mystic Mountain is the term for a dust–gas pillar in the Carina Nebula, a photo of which was taken by Hubble Space Telescope on its 20th anniversary. The area was observed by Hubble's Wide Field Camera 3 on 1–2 February 2010. The pillar measures Template:Convert in height; nascent stars inside the pillar fire off gas jets that stream from towering “peaks”.

WR 22Edit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} WR 22 is an eclipsing binary. The dynamical masses derived from orbital fitting vary from over Template:Solar mass to less than Template:Solar mass for the primary and about Template:Solar mass for the secondary.<ref name="revised">Template:Cite journal</ref> The spectroscopic mass of the primary has been calculated at Template:Solar mass<ref name=hamann>Template:Cite journal</ref> or Template:Solar mass.<ref name=grafener>Template:Cite journal</ref>

WR 25Edit

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WR 25 is a binary system in the central portion of the Carina Nebula, a member of the Template:Nowrap cluster. The primary is a Wolf–Rayet star, possibly the most luminous star in the galaxy. The secondary is hard to detect but thought to be a luminous OB star.

HD 93129Edit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} HD 93129 is a triple star system of O-class stars in Carina. All three stars of Template:Nowrap are among the most luminous in the galaxy;<ref name="cohen">Template:Cite journal</ref> Template:Nowrap consists of two clearly resolved components, Template:Nowrap and Template:Nowrap, and Template:Nowrap itself is made up of two much closer stars.

HD 93129 A has been resolved into two components. The spectrum is dominated by the brighter component, although the secondary is only 0.9 magnitudes fainter. Template:Nowrap is an O2 supergiant and Ab is an O3.5 main sequence star.<ref name="benaglia">Template:Cite journal</ref> Their separation has decreased from 55 milliarcseconds in 2004 to only 27 mas in 2013, but an accurate orbit is not available.<ref name="sana">Template:Cite journal</ref>

HD 93129 B is an O3.5 main-sequence star 3 arcseconds away from the closer pair. It is about 1.5 magnitudes fainter than the combined Template:Nowrap, and is approximately the same brightness as Template:Nowrap.<ref name="tycho2">Template:Cite journal</ref><ref name="vazquez">Template:Cite journal</ref>

HD 93250Edit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} HD 93250 is one of the brightest stars in the region of the Carina Nebula. It is only 7.5 arcminutes from Eta Carinae,<ref name="sana2011">Template:Cite journal</ref> and Template:Nowrap is considered to be a member of the same loose open cluster Template:Nowrap, although it appears closer to the more compact Template:Nowrap.<ref name="smith2006mnras">Template:Cite journal</ref>

HD 93250 is known to be a binary star, however, individual spectra of the two components have never been observed but are thought to be very similar. The spectral type of Template:Nowrap has variously been given as O5,<ref name="thackeray1973">Template:Cite journal</ref> O6/7,<ref name="houk1975">Template:Cite book</ref> O4,<ref name="walborn2010">Template:Cite journal</ref> and O3.<ref name="williams2011">Template:Cite journal</ref> It has sometimes been classified as a main sequence star and sometimes as a giant star.<ref name="walborn2010" /><ref name="williams2011" /> The Galactic O-Star Spectroscopic Survey has used it as the standard star for the newly created O4 subgiant spectral type.<ref name="gosss">Template:Cite journal</ref>

HD 93205Edit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} HD 93205 is a binary system of two large stars.

The more massive member of the pair is an O3.5 main sequence star. The spectrum shows some ionized nitrogen and helium emission lines, indicating some mixing of fusion products to the surface and a strong stellar wind. The mass calculated from apsidal motion of the orbits is Template:Solar mass. This is somewhat lower than expected from evolutionary modelling of a star with its observed parameters.<ref name="benvenuto2002">Template:Cite journal</ref>

The less massive member is an O8 main sequence star of approximately Template:Solar mass.<ref name="antokhina2000">Template:Cite journal</ref> It moves in its orbit at a speed of over Template:Convert and is considered to be a relativistic binary, which causes the apses of the orbit to change in a predictable way.<ref name="morrell2001">Template:Cite journal</ref>

Catalogued open clusters in Carina NebulaEdit

Template:As of, there are eight known open clusters in the Carina Nebula:<ref name="messier.seds.org"/>

  • Bochum 10 (Bo 10)
  • Bochum 11 (Bo 11)
  • Collinder 228 (Cr 228)<ref name="seds-cr228">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

  • Collinder 232 (Cr 232)
  • Collinder 234 (Cr 234)
  • Trumpler 14 (Tr 14, Cr 230)
  • Trumpler 15 (Tr 15, Cr 231)
  • Trumpler 16 (Tr 16, Cr 233)

Annotated mapEdit

File:NGC 3372d.jpg
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File:Regioni celesti scelte - CarinaNebula.png
A celestial map of the nebula.

GalleryEdit

See alsoEdit

ReferencesEdit

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External linksEdit

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Template:Catalogs Template:RCW Template:Caldwell catalogue Template:Ngc35 Template:Carina (constellation) Template:Portal bar