Carina Nebula#Keyhole Nebula
{{short description|Interstellar clouds in the constellation Carina}}
{{Use dmy dates|date=October 2019}}
{{Infobox nebula
| name = Carina Nebula
| type = Emission
| image = Carina Nebula by Harel Boren (151851961, modified).jpg
| caption = The Carina Nebula. Eta Carinae and the Keyhole Nebula are left of center, NGC 3324 is at upper right.
| epoch = J2000.0
| ra = {{RA|10|45|08.5}}{{cite web |url=http://www.ngcicproject.org/pubdb.htm |title=NGC 3372 |website=The NGC/IC Project |access-date=29 November 2016 |archive-url=https://web.archive.org/web/20090528100240/http://www.ngcicproject.org/pubdb.htm |archive-date=28 May 2009 |url-status=dead}}
| dist_ly = ~8,500
| size_v = 120 × 120 arcmins
| constellation = Carina
| radius_pc = ~70
| absmag_v =
| notes = {{plainlist|
- Eta Carinae
- Keyhole Nebula
- Many open clusters & dark nebulae}}
| names = NGC 3372,{{cite simbad |title=NGC 3372 |access-date=3 September 2013}} ESO 128-EN013, GC 2197, h 3295, Caldwell 92{{cite book |title=The Caldwell Objects |pages=361–369 |publisher=Cambridge University Press |last=O'Meara |first=S. J. |year=2002 |isbn=978-0-521-82796-6}}}}
{{Sky|10|45|08.5|-|59|52|04|100000}}
File:NASA’s Webb Reveals Cosmic Cliffs, Glittering Landscape of Star Birth.jpg, one of the first images taken by the James Webb Space Telescope]]
The Carina Nebula{{cite web |url=https://hubblesite.org/contents/media/images/2007/16/2099-Image.html |title=The Carina Nebula: Star Birth in the Extreme |author= |date=24 April 2007 |website=Hubblesite |publisher=NASA |access-date=20 November 2020}} or Eta Carinae NebulaUranometria 2000.0 (catalogued as NGC 3372; also known as the Great Carina NebulaAPOD, [https://apod.nasa.gov/apod/ap181227.html Picture of the day for 27 Dec 2018]) 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 {{convert|8500|ly|pc|lk=on}} from Earth.
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. {{nowrap|Carina OB1}} encompasses the star clusters {{nowrap|Trumpler 14}} and {{nowrap|Trumpler 16}}. {{nowrap|Trumpler 14}} is one of the youngest known star clusters at half a million years old and contains stars like the O2 supergiant {{nowrap|HD 93129A}}. {{nowrap|Trumpler 16}} is the home of many extremely luminous stars, such as {{nowrap|WR 25}} and the Eta Carinae star system. {{nowrap|Trumpler 15}}, {{nowrap|Collinder 228}}, {{nowrap|Collinder 232}}, {{nowrap|NGC 3324}}, and {{nowrap|NGC 3293}} are also considered members of the association. {{nowrap|NGC 3293}} is the oldest and furthest from {{nowrap|Trumpler 14}}, indicating sequential and ongoing star formation.
The nebula is one of the largest diffuse nebulae in Earth's sky. 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.{{Cite web |last=Garner |first=Rob |date=2022-07-08 |title=NASA Shares List of Cosmic Targets for Webb Telescope's 1st Images |url=http://www.nasa.gov/feature/goddard/2022/nasa-shares-list-of-cosmic-targets-for-webb-telescope-s-first-images |access-date=2022-07-08 |website=NASA}}
Discovery and basic information
Nicolas-Louis de Lacaille discovered the nebula on 25 January 1752.{{cite journal
| title=The search for the nebulae - VI
| last=Jones | first=K. G.
| journal=Journal of the British Astronomical Association
| volume=79 | pages=213–222 | date=March 1969
| bibcode=1969JBAA...79..213J
}} Its dimensions are 120×120 arcminutes centered on the coordinates of right ascension {{RA|10|45|08.5}} and declination {{DEC|-59|52|04}}. In modern times it is calculated to be around {{convert|8500|ly|pc|lk=on}} from Earth.
Objects within the Carina Nebula
=Eta Carinae=
{{main|Eta Carinae}}
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 Nebula=
{{main|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.{{cite journal |title=Near-infrared integral field spectroscopy of the Homunculus nebula around η Carinae using Gemini/CIRPASS |journal=Monthly Notices of the Royal Astronomical Society |last1=Teodoro |first1=M. |last2=Damineli |first2=A. |last3=Sharp |first3=R. G. |last4=Groh |first4=J. H. |last5=Barbosa |first5=C. L. |display-authors=1 |volume=387 |issue=2 |pages=564–576 |date=June 2008 |doi=10.1111/j.1365-2966.2008.13264.x |doi-access=free |bibcode=2008MNRAS.387..564T |arxiv=0804.0240|s2cid=2460614 }} 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.{{cite book |title=Eta Carinae and the Supernova Impostors |series=Astrophysics and Space Science Library, Volume 384 |publisher=Springer Science+Business Media |editor1-first=Kris |editor1-last=Davidson |editor2-first=Roberta M. |editor2-last=Humphreys |date=23 January 2012 |volume=384 |isbn=978-1-4614-2274-7 |doi=10.1007/978-1-4614-2275-4 |bibcode=2012ASSL..384.....D |url=https://cds.cern.ch/record/1453273|last1=Davidson |first1=Kris |last2=Humphreys |first2=Roberta M. }}{{rp|145–169}}
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 {{convert|2.35|±|0.05|kpc|ly pc|order=out|lk=on}}. 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".{{cite journal |title=The Structure of the Homunculus. I. Shape and Latitude Dependence from H2 and [Fe II] Velocity Maps of η Carinae |journal=The Astrophysical Journal |last1=Smith |first1=Nathan |volume=644 |issue=2 |pages=1151–1163 |date=June 2006 |doi=10.1086/503766 |bibcode=2006ApJ...644.1151S |arxiv=astro-ph/0602464|s2cid=12453761 }}
=Keyhole Nebula=
File:Keyhole in the Carina Nebula (eso0905a crop).jpg
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,{{cite book |url=https://books.google.com/books?id=8WBNAAAAcAAJ&q=Canopus&pg=PA33 |title=Results of astronomical observations made during the years 1834, 5, 6, 7, 8, at the Cape of Good Hope: Being the completion of a telescopic survey of the whole surface of the visible heavens, commenced in 1825 |volume=1 |publisher=Smith, Elder and Co. |location=London |first=John Frederick William |last=Herschel |pages=33–35 |year=1847 |oclc=5045340 |bibcode=1847raom.book.....H}} and subsequently referred to it simply as the "oval vacuity".{{cite journal |title=Catalogue of Nebulae and Clusters of Stars |journal=Philosophical Transactions of the Royal Society of London |last=Herschel |first=John Frederick William |volume=154 |pages=1–137 |date=1864 |doi=10.1098/rstl.1864.0001 |bibcode=1864RSPT..154....1H|doi-access=free }} The term lemniscate continued to be used to describe this portion of the nebula{{cite journal |title=Eta Argus |journal=Astronomical Register |last=Abbott |first=F. |volume=11 |pages=221–224 |date=1873 |bibcode=1873AReg...11..221A}} until popular astronomy writer Emma Converse described the shape of the nebula as "resembling a keyhole" in an 1873 Appleton's Journal article.{{cite journal |url=https://books.google.com/books?id=BgMZAAAAYAAJ&pg=PA818 |title=Eta Argûs |journal=Appletons' Journal |first=Emma M. |last=Converse |volume=10 |issue=249 |page=818 |date=27 December 1873}} 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").{{cite journal |title=The spectrum of η Carinae |journal=Lick Observatory Bulletin |first1=Joseph Haines |last1=Moore |first2=Roscoe Frank |last2=Sanford |name-list-style=amp |volume=8 |issue=252 |pages=55–61 |date=1914 |doi=10.5479/ADS/bib/1914LicOB.8.55M |bibcode=1914LicOB...8...55M}}See, e.g., {{cite book |title=Burnham's Celestial Handbook |publisher=Dover |location=New York |first=Robert |last=Burnham, Jr |page=467 |date=1978 |isbn=978-0-486-23567-7}}
The diameter of the Keyhole structure is approximately {{convert|7|ly|pc|spell=in}}. Its appearance has changed significantly since it was first observed, possibly due to changes in the ionizing radiation from Eta Carinae.{{cite journal |title=Structure in the Carina Nebula and Eta Carinae |journal=Sky and Telescope |last1=Walborn |first1=N. R. |author1-link=Nolan R. Walborn |last2=Ingerson |first2=T. E. |name-list-style=amp |volume=54 |pages=22–24 |date=July 1977 |bibcode=1977S&T....54...22W}} The Keyhole does not have its own NGC designation. It is sometimes erroneously called NGC 3324,For example, see [http://apod.nasa.gov/apod/ap990523.html APOD – NGC 3324]. but that catalogue designation refers to a reflection and emission nebula just northwest of the Carina Nebula (or to its embedded star cluster).{{cite book |title=The Night Sky Observer's Guide |series=Volume 3: The Southern Skies |publisher=Willmann-Bell |first1=Ian |last1=Cooper |first2=Jenni |last2=Kay |first3=George Robert |last3=Kepple |display-authors=1 |page=52 |date=2008 |isbn=978-0-943396-89-7}}{{cite web |url=http://www.ngcicproject.org/pubdb.htm |title=NGC 3324 |website=The NGC/IC Project |access-date=17 May 2014 |archive-url=https://web.archive.org/web/20090528100240/http://www.ngcicproject.org/pubdb.htm |archive-date=28 May 2009 |url-status=dead}}{{cite simbad |title=NGC 3324 |access-date=17 May 2014}}
=Defiant Finger=
{{Main|Finger of God Globule}}
File:"Finger of God" Bok globule in the Carina Nebula.jpg
A small Bok globule in the Keyhole Nebula (at RA 10h{{nbsp}}44m{{nbsp}}30s, Dec −59°{{nbsp}}40') has been photographed by the Hubble Space Telescope and is nicknamed the "Carina Defiant Finger" due to its shape.{{cite simbad|title=NAME Carina Defiant Finger|access-date=2020-04-03}} 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 {{solar mass|6}}, 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.{{cite journal|bibcode=2004MNRAS.351.1457S|title=Carina's defiant Finger: HST observations of a photoevaporating globule in NGC 3372*|last1=Smith|first1=Nathan|last2=Barbá|first2=Rodolfo H.|last3=Walborn|first3=Nolan R.|journal=Monthly Notices of the Royal Astronomical Society|year=2004|volume=351|issue=4|pages=1457|doi=10.1111/j.1365-2966.2004.07894.x|doi-access=free |arxiv=astro-ph/0404495|s2cid=14709621 }}
=Trumpler 14=
{{main|Trumpler 14}}
File:Trumpler 14 by Hubble.jpg
Trumpler 14 is an open cluster with a diameter of {{convert|6|ly|pc|spell=in}}, located within the inner regions of the Carina Nebula, approximately {{convert|8000|ly|pc}} from Earth.{{cite journal |title=New catalogue of optically visible open clusters and candidates |journal=Astronomy & Astrophysics |first1=W. S. |last1=Dias |first2=B. S. |last2=Alessi |first3=A. |last3=Moitinho |first4=J. R. D. |last4=Lépine |display-authors=1 |volume=389 |issue=3 |pages=871–873 |date=July 2002 |bibcode=2002A&A...389..871D |doi=10.1051/0004-6361:20020668 |arxiv=astro-ph/0203351|s2cid=18502004 }} It is one of the main clusters of the {{nowrap|Carina OB1}} stellar association, which is the largest association in the Carina Nebula. About 2,000 stars have been identified in {{nowrap|Trumpler 14}}.{{cite journal |url=http://www.eso.org/public/news/eso0947/ |title=Stellar Family Portrait Takes Imaging Technique to New Extremes |journal=European Southern Observatory Press Release |publisher=European Southern Observatory |date=3 December 2009 |page=47 |bibcode=2009eso..pres...47. |id=Science Release eso0947}} and the total mass of the cluster is estimated to be {{solar mass|4,300|link=yes}}.{{cite journal |title=A MAD view of Trumpler 14 |journal=Astronomy & Astrophysics |first1=H. |last1=Sana |first2=Y. |last2=Momany |first3=M. |last3=Gieles |first4=Y. |last4=Beletsky |first5=V. D. |last5=Ivanov |first6=G. |last6=de Silva |first7=G. |last7=James |display-authors=1 |volume=515 |at=A26 |date=June 2010 |doi=10.1051/0004-6361/200913688 |bibcode=2010A&A...515A..26S |arxiv=1003.2208|s2cid=119294869 }}
=Trumpler 15=
{{main|Trumpler 15}}
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.
=Trumpler 16=
{{main|Trumpler 16}}
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 {{nowrap|Trumpler 14}}. The star Eta Carinae is part of this cluster.
=Mystic Mountain=
{{main|Mystic Mountain}}
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 {{convert|3|ly|pc|spell=in}} in height; nascent stars inside the pillar fire off gas jets that stream from towering “peaks”.
=WR 22=
{{main|WR 22}}
WR 22 is an eclipsing binary. The dynamical masses derived from orbital fitting vary from over {{solar mass|70}} to less than {{solar mass|60}} for the primary and about {{solar mass|21 to 27}} for the secondary.{{cite journal |title=Revised mass determination of the super massive Wolf-Rayet star WR 22 |journal=Astronomy & Astrophysics |first1=J. |last1=Schweickhardt |first2=W. |last2=Schmutz |first3=O. |last3=Stahl |first4=Th. |last4=Szeifert |first5=B. |last5=Wolf |display-authors=1 |volume=347 |issue=1 |pages=127–136 |date=July 1999 |bibcode=1999A&A...347..127S}} The spectroscopic mass of the primary has been calculated at {{solar mass|74}}{{cite journal |title=The Galactic WN stars. Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation |journal=Astronomy & Astrophysics |last1=Hamann |first1=W.-R. |last2=Gräfener |first2=G. |last3=Liermann |first3=A. |display-authors=1 |volume=457 |issue=3 |pages=1015–1031 |date=October 2006 |doi=10.1051/0004-6361:20065052 |bibcode=2006A&A...457.1015H |arxiv=astro-ph/0608078|s2cid=18714731 }} or {{solar mass|78.1}}.{{cite journal |title=Mass loss from late-type WN stars and its Z-dependence. Very massive stars approaching the Eddington limit |journal=Astronomy & Astrophysics |last1=Gräfener |first1=G. |last2=Hamann |first2=W.-R. |name-list-style=amp |volume=482 |issue=3 |pages=945–960 |date=May 2008 |doi=10.1051/0004-6361:20066176 |bibcode=2008A&A...482..945G |arxiv=0803.0866|s2cid=16025012 }}
=WR 25=
{{main|WR 25}}
File:WR 25 and Tr16-244 region (cropped).jpg
WR 25 is a binary system in the central portion of the Carina Nebula, a member of the {{nowrap|Trumpler 16}} 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 93129=
{{main|HD 93129}}
HD 93129 is a triple star system of O-class stars in Carina. All three stars of {{nowrap|HD 93129}} are among the most luminous in the galaxy;{{Cite journal |title=Chandra X-ray spectroscopy of the very early O supergiant HD 93129A: Constraints on wind shocks and the mass-loss rate |journal=Monthly Notices of the Royal Astronomical Society |last1=Cohen |first1=D. H. |last2=Gagné |first2=M. |last3=Leutenegger |first3=M. A. |last4=MacArthur |first4=J. P. |last5=Wollman |first5=E. E. |last6=Sundqvist |first6=J. O. |last7=Fullerton |first7=A. W. |last8=Owocki |first8=S. P. |display-authors=1 |volume=415 |issue=4 |pages=3354–3364 |date=August 2011 |doi=10.1111/j.1365-2966.2011.18952.x |doi-access=free |bibcode=2011MNRAS.415.3354C |arxiv=1104.4786|s2cid=8258609 }} {{nowrap|HD 93129}} consists of two clearly resolved components, {{nowrap|HD 93129 A}} and {{nowrap|HD 93129 B}}, and {{nowrap|HD 93129 A}} 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. {{nowrap|HD 93129 Aa}} is an O2 supergiant and Ab is an O3.5 main sequence star.{{cite journal |title=Radio observations of HD 93129A: The earliest O star with the highest mass loss? |journal=Astronomy & Astrophysics |first1=P. |last1=Benaglia |first2=B. |last2=Koribalski |name-list-style=amp |volume=416 |issue=1 |pages=171–178 |date=March 2004 |doi=10.1051/0004-6361:20034138 |bibcode=2004A&A...416..171B |arxiv=astro-ph/0312003|s2cid=18416034 }} Their separation has decreased from 55 milliarcseconds in 2004 to only 27 mas in 2013, but an accurate orbit is not available.{{cite journal |title=Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection |journal=The Astrophysical Journal Supplement |last1=Sana |first1=H. |last2=Le Bouquin |first2=J.-B. |last3=Lacour |first3=S. |last4=Berger |first4=J.-P. |last5=Duvert |first5=G. |last6=Gauchet |first6=L. |last7=Norris |first7=B. |last8=Olofsson |first8=J. |last9=Pickel |first9=D. |last10=Zins |first10=G. |last11=Absil |first11=O. |last12=De Koter |first12=A. |last13=Kratter |first13=K. |last14=Schnurr |first14=O. |last15=Zinnecker |first15=H. |display-authors=1 |volume=215 |issue=1 |at=15 |date=November 2014 |doi=10.1088/0067-0049/215/1/15 |bibcode=2014ApJS..215...15S |arxiv=1409.6304|s2cid=53500788 }}
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 {{nowrap|HD 93129 A}}, and is approximately the same brightness as {{nowrap|HD 93129 Ab}}.{{cite journal |title=The Tycho-2 catalogue of the 2.5 million brightest stars |journal=Astronomy & Astrophysics |last1=Høg |first1=E. |last2=Fabricius |first2=C. |last3=Makarov |first3=V. V. |last4=Urban |first4=S. |last5=Corbin |first5=T. |last6=Wycoff |first6=G. |last7=Bastian |first7=U. |last8=Schwekendiek |first8=P. |last9=Wicenec |first9=A. |display-authors=1 |volume=355 |pages=L27–L30 |date=March 2000 |bibcode=2000A&A...355L..27H}}{{cite journal |title=Investigation on the region of the open cluster TR 14 |journal=Astronomy and Astrophysics Supplement |last1=Vazquez |first1=R. A. |last2=Baume |first2=G. |last3=Feinstein |first3=A. |last4=Prado |first4=P. |display-authors=1 |volume=116 |pages=75–94 |date=March 1996 |bibcode=1996A&AS..116...75V}}
=HD 93250=
{{main|HD 93250}}
HD 93250 is one of the brightest stars in the region of the Carina Nebula. It is only 7.5 arcminutes from Eta Carinae,{{cite journal |title=The Non-thermal Radio Emitter HD 93250 Resolved by Long Baseline Interferometry |journal=The Astrophysical Journal Letters |last1=Sana |first1=H. |last2=Le Bouquin |first2=J.-B. |last3=De Becker |first3=M. |last4=Berger |first4=J.-P. |last5=De Koter |first5=A. |last6=Mérand |first6=A. |display-authors=1 |volume=740 |issue=2 |at=L43 |date=October 2011 |doi=10.1088/2041-8205/740/2/L43 |bibcode=2011ApJ...740L..43S |arxiv=1110.0831|s2cid=119215270 }} and {{nowrap|HD 93250}} is considered to be a member of the same loose open cluster {{nowrap|Trumpler 16}}, although it appears closer to the more compact {{nowrap|Trumpler 14}}.{{cite journal |title=A census of the Carina Nebula. I. Cumulative energy input from massive stars |journal=Monthly Notices of the Royal Astronomical Society |last1=Smith |first1=Nathan |volume=367 |issue=2 |pages=763–772 |date=April 2006 |doi=10.1111/j.1365-2966.2006.10007.x |doi-access=free |bibcode=2006MNRAS.367..763S |arxiv=astro-ph/0601060|s2cid=14060690 }}
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 {{nowrap|HD 93250}} has variously been given as O5,{{cite journal |title=Radial velocities of southern B stars determined at the Radcliffe Observatory—VII |journal=Memoirs of the Royal Astronomical Society |last1=Thackeray |first1=A. D. |last2=Tritton |first2=S. B. |last3=Walker |first3=E. N. |display-authors=1 |volume=77 |pages=199 |date=1973 |bibcode=1973MmRAS..77..199T}} O6/7,{{cite book |title=University of Michigan Catalogue of Two-Dimensional Spectral Types for the HD Stars. Volume 1. Declinations −90° to −53° |publisher=Department of Astronomy, University of Michigan |last1=Houk |first1=Nancy |last2=Cowley |first2=Anne P. |name-list-style=amp |date=1975 |isbn=978-0-8357-0331-4 |bibcode=1975mcts.book.....H}} O4,{{cite journal |title=Early Results from the Galactic O-Star Spectroscopic Survey: C III Emission Lines in of Spectra |journal=The Astrophysical Journal Letters |last1=Walborn |first1=Nolan R. |last2=Sota |first2=Alfredo |last3=Maíz Apellániz |first3=Jesús |last4=Alfaro |first4=Emilio J. |last5=Morrell |first5=Nidia I. |last6=Barbá |first6=Rodolfo H. |last7=Arias |first7=Julia I. |last8=Gamen |first8=Roberto C. |display-authors=1 |volume=711 |issue=2 |pages=L143–L147 |date=March 2010 |doi=10.1088/2041-8205/711/2/L143 |bibcode=2010ApJ...711L.143W |arxiv=1002.3293|s2cid=119122481 }} and O3.{{cite journal |title=Radial Velocities of Galactic O-type Stars. I. Short-term Constant Velocity Stars |journal=The Astronomical Journal |last1=Williams |first1=S. J. |last2=Gies |first2=D. R. |last3=Hillwig |first3=T. C. |last4=McSwain |first4=M. V. |last5=Huang |first5=W. |display-authors=1 |volume=142 |issue=5 |at=146 |date=November 2011 |doi=10.1088/0004-6256/142/5/146 |bibcode=2011AJ....142..146W|doi-access=free }} It has sometimes been classified as a main sequence star and sometimes as a giant star. The Galactic O-Star Spectroscopic Survey has used it as the standard star for the newly created O4 subgiant spectral type.{{cite journal |title=The Galactic O-Star Spectroscopic Survey (GOSSS). III. 142 Additional O-type Systems |journal=The Astrophysical Journal Supplement Series |last1=Maíz Apellániz |first1=J. |last2=Sota |first2=A. |last3=Arias |first3=J. I. |last4=Barbá |first4=R. H. |last5=Walborn |first5=N. R. |last6=Simón-Díaz |first6=S. |last7=Negueruela |first7=I. |last8=Marco |first8=A. |last9=Leão |first9=J. R. S. |last10=Herrero |first10=A. |last11=Gamen |first11=R. C. |last12=Alfaro |first12=E. J. |display-authors=1 |volume=224 |issue=1 |at=4 |date=May 2016 |doi=10.3847/0067-0049/224/1/4 |bibcode=2016ApJS..224....4M |arxiv=1602.01336|s2cid=55658165 |doi-access=free }}
=HD 93205=
{{main|HD 93205}}
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 {{solar mass|40 to 60}}. This is somewhat lower than expected from evolutionary modelling of a star with its observed parameters.{{cite journal |title=Calculation of the masses of the binary star HD 93205 by application of the theory of apsidal motion |journal=Monthly Notices of the Royal Astronomical Society |last1=Benvenuto |first1=O. G. |last2=Serenelli |first2=A. M. |last3=Althaus |first3=L. G. |last4=Barbá |first4=R. H. |last5=Morrell |first5=N. I. |display-authors=1 |volume=330 |issue=2 |pages=435–442 |date=February 2002 |doi=10.1046/j.1365-8711.2002.05083.x |doi-access=free |bibcode=2002MNRAS.330..435B |arxiv=astro-ph/0110662|s2cid=16834579 }}
The less massive member is an O8 main sequence star of approximately {{solar mass|20}}.{{cite journal |title=Light Curve Solution of HD 93205 (O3 V+O8 V) Containing the Earliest Known Star in a Well-studied Binary |journal=The Astrophysical Journal |first1=Eleonora A. |last1=Antokhina |first2=Anthony F. J. |last2=Moffat |first3=Igor I. |last3=Antokhin |first4=Jean-François |last4=Bertrand |first5=Robert |last5=Lamontagne |display-authors=1 |volume=529 |issue=1 |pages=463–476 |date=January 2000 |doi=10.1086/308228 |bibcode=2000ApJ...529..463A|s2cid=117107602 |doi-access=free }} It moves in its orbit at a speed of over {{convert|300|km/s|mi/s|abbr=on}} and is considered to be a relativistic binary, which causes the apses of the orbit to change in a predictable way.{{cite journal |url=http://orbi.ulg.ac.be/bitstream/2268/34118/1/0105014.pdf |title=Optical spectroscopy of X-Mega targets – II. The massive double-lined O-type binary HD 93205 |journal=Monthly Notices of the Royal Astronomical Society |last1=Morrell |first1=N. I. |last2=Barbá |first2=R. H. |last3=Niemela |first3=V. S. |last4=Corti |first4=M. A. |last5=Albacete Colombo |first5=J. F. |last6=Rauw |first6=G. |last7=Corcoran |first7=M. |last8=Morel |first8=T. |last9=Bertrand |first9=J.-F. |last10=Moffat |first10=A. F. J. |last11=St-Louis |first11=N. |display-authors=1 |volume=326 |issue=1 |pages=85–94 |date=September 2001 |doi=10.1046/j.1365-8711.2001.04500.x |doi-access=free |bibcode=2001MNRAS.326...85M |arxiv=astro-ph/0105014|s2cid=16221731 }}
Catalogued open clusters in Carina Nebula
{{As of|1998}}, there are eight known open clusters in the Carina Nebula:
- Bochum 10 (Bo 10)
- Bochum 11 (Bo 11)
- Collinder 228 (Cr 228){{cite web |url=http://messier.seds.org/xtra/ngc/cr228.html |title=Collinder 228 |website=SEDS.org |first1=Hartmut |last1=Frommert |first2=Christine |last2=Kronberg |name-list-style=amp |date=6 May 2001 |access-date=29 November 2016}}
- 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 map
Gallery
File:The spectacular star-forming Carina Nebula imaged by the VLT Survey Telescope.jpg|Overview of the Carina Nebula. The Keyhole is superimposed on the bright area above center, and Eta Carinae is the bright star just to its left.
File:The Carina Nebula in infrared light.jpg|Carina Nebula in infrared light{{cite web |url=https://www.eso.org/public/news/eso1828/ |title=Stars v. Dust in the Carina Nebula |publisher=European Southern Observatory |date=29 August 2018 |access-date=30 August 2018}}
File:Nearby Supernova Factory Ramps Up- A star-forming region about 7,500 light years from Earth. (6261054663).jpg|X-rays from stars and diffuse multimillion-Kelvin plasma light up the Carina Nebula in this Chandra X-ray Observatory image
File:ESO - The Carina Nebula (by).jpg|Close-up of the Carina Nebula's central region
File:Carina Nebula around the Wolf–Rayet star WR 22.jpg|Wolf–Rayet star WR 22
File:Hs-2007-16-e-800x800.jpg|Bok globule nicknamed "The Caterpillar"{{cite web |url=https://hubblesite.org/contents/media/images/2007/16/2104-Image.html |title=Carina Nebula Details: The Caterpillar |work=Hubblesite |publisher=Space Telescope Science Institute |date=24 April 2007 |access-date=14 August 2023}}
File:Region R44 in the Carina Nebula.jpg|Region R44 in the Carina Nebula{{cite web |url=https://www.eso.org/public/news/eso1639/ |title=Pillars of Destruction |publisher=European Southern Observatory |date=2 November 2016 |access-date=7 December 2016}}
File:Carina Nebula Jets (NIRCam Narrowband Filters - Annotated) (carinanebula1).jpeg|Scientists taking a “deep dive” into one of the iconic first images from the James Webb Space Telescope have discovered dozens of energetic jets and outflows from young stars previously hidden by dust clouds. {{cite news |url=https://esawebb.org/images/carinanebula1/|title=Carina Nebula Jets (NIRCam Narrowband Filters - Annotated)|date=October 18, 2023}}
See also
References
{{Reflist|30em}}
External links
{{Commons category}}
- [http://messier.seds.org/xtra/ngc/n3372.html Carina Nebula] at SEDS.org
- [http://www.atlasoftheuniverse.com/nebulae/ngc3372.html Carina Nebula] at Atlas of the Universe
- [http://www.constellation-guide.com/carina-nebula/ Carina Nebula] at Constellation Guide
- {{WikiSky}}
{{Catalogs|NGC=3372|C=92|GC=2197|RCW=53}}
{{RCW}}
{{Caldwell catalogue}}
{{Ngc35}}
{{Carina (constellation)}}
{{Portal bar|Astronomy|Stars|Outer space}}
{{DEFAULTSORT:Carina Nebula}}
Category:Carina (constellation)
Category:Carina–Sagittarius Arm