Carina Nebula

From Wikipedia, the free encyclopedia
  (Redirected from Eta Carinae Nebula)
Jump to: navigation, search
Carina Nebula
Carina Nebula.jpg
An image of NGC 3372 taken by the ESO VLT telescope
Observation data: J2000.0 epoch
Type Emission
Right ascension 10h 45m 08.5s[1]
Declination −59° 52′ 04″[1]
Distance ~6500-10000 ly [1]
Apparent magnitude (V) +1.0
Constellation Carina
Physical characteristics
Radius ~100 pc[2]
Absolute magnitude (V) ~10.8
Notable features Includes dark nebula
Keyhole Nebula
Other designations NGC 3372,[3] ESO 128-EN013,[1] GC 2197,[1] Caldwell 92[4]
See also: Diffuse nebula, Lists of nebulae

Coordinates: Sky map 10h 45m 08.5s, −59° 52′ 04″

The Carina Nebula (also known as the Great Nebula in Carina, the Eta Carinae Nebula, NGC 3372, as well as the Grand Nebula) is a large bright nebula that has within its boundaries several related open clusters of stars. Some papers generally refer to this as the Carina Nebula, mostly because of differentiating the many paper published on this object, but the historical precedence as determined by southern observers like James Dunlop and John Herschel, who have both termed it the Eta Argus Nebula or Eta Carinae Nebula.[5] John Herschel also describes "The star η Argus, with the Great nebula about it."[6] with many of his subsequent published papers supporting this.[7][8]

Eta Carinae and HD 93129A, two of the most massive and luminous stars in our Milky Way galaxy, are among them. The nebula lies at an estimated distance between 6,500 and 10,000 light years from Earth. It appears in the constellation of Carina, and is located in the Carina–Sagittarius Arm. The nebula contains multiple O-type stars.

The nebula is one of the largest diffuse nebulae in our skies. Although it is some four times as large 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 1751–52 from the Cape of Good Hope.

Objects within the Carina Nebula[edit]

Eta Carinae[edit]

Carina Nebula, glowing intensely red in the middle of the image.[9]

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. The dark globules in the above image 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 around Eta Carinae

Homunculus Nebula[edit]

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

Keyhole Nebula[edit]

A portion of the Carina Nebula is known as the Keyhole Nebula, a name given to it by John Herschel in the 19th century. The Keyhole Nebula is actually a much smaller and darker cloud of cold molecules and dust, containing bright filaments of hot, fluorescing gas, silhouetted against the much brighter background nebula. The diameter of the Keyhole structure is approximately 7 light years. NGC 3324 is a designation for the Keyhole Nebula.[10]

Mystic Mountain[edit]

The "Mystic Mountain" is an image of a dust–gas pillar in the Carina Nebula taken by Hubble Space Telescope on its 20th anniversary. The area was observed by Hubble’s Wide Field Camera 3 on February 1–2, 2010. The pillar measures three light years in height; nascent stars inside the pillar fire off gas jets, that stream from towering peaks.

Gallery[edit]

Tour of the Carina Nebula.
Carina Nebula.
This video starts from a wide-field view of the constellation of Carina (The Keel), and zooms in to the Carina Nebula region.
This zoom sequence starts with a broad view of the Milky Way and closes in on the Carina Nebula. In the final sequence we see a new image taken in infrared light using the HAWK-I camera on ESO’s Very Large Telescope. Many previously hidden features, scattered across a spectacular celestial landscape of gas, dust and young stars, have emerged.
This video sequence compares a view of the Carina Nebula taken in visible light with a new picture taken in infrared light. The visible-light view comes from the MPG/ESO 2.2-metre telescope at the La Silla Observatory and the new infrared picture comes from the HAWK-I camera on ESO’s Very Large Telescope. Many new features that are not seen at all in visible light can be seen in great detail in the new sharp infrared image from the VLT.

References[edit]

  1. ^ a b c d e "Object Data – NGC 3372". The NGC/IC Project. Archived from the original on 2008-05-12. Retrieved 2008-04-25. 
  2. ^ "NGC 3372 - The Eta Carinae Nebula". Atlas of the Universe. Retrieved 2013-10-01. 
  3. ^ "NGC 3372". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-09-03. 
  4. ^ O'Meara, S. J. (2002). The Caldwell Objects. Cambridge University Press. pp. 361–369. ISBN 0-521-82796-5. 
  5. ^ Dunlop, J. (1838). "A Catalogue of Nebulae and Clusters of Stars in the Southern Hemisphere, Observed at Paramatta in New South Wales". Philosophical Transactions of the Royal Society 118: 113. Bibcode:1828RSPT..118..113D. JSTOR 107841. 
  6. ^ Herschel, F. W. (1847). 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. Smith, Elder & Co. Bibcode:1847QB3.H52........ 
  7. ^ Herschel, J. F. W. (1864). "Catalogue of Nebulae and Clusters of Stars". Philosophical Transactions of the Royal Society of London 154: 1–137. Bibcode:1864RSPT..154....1H. doi:10.1098/rstl.1864.0001. JSTOR 108864. 
  8. ^ Dreyer, J. L. E. (1888). "A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged". Memoirs of the Royal Astronomical Society 49: 1–237. Bibcode:1888MmRAS..49....1D. 
  9. ^ "One Picture, Many Stories". ESO Picture of the Week. Retrieved 13 February 2013. 
  10. ^ APOD - NGC 3324

External links[edit]