N119

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N119
Emission nebula
H II region
Eso9931d.jpg
MPG/ESO telescope Wide Field Imager blue, green, and H-alpha image of N119
Observation data: J2000.0 epoch
Subtype Emission nebula
Right ascension 5h 18m 45s [1]
Declination −69° 14′ 03″ [1]
Distance160,000  ly    (50,000  pc)
Apparent magnitude (V)5.60
Apparent dimensions (V)9′ 14″ × 12′ 15″ [note 1]
Constellation Dorado
Physical characteristics
Absolute magnitude (V)−13 (1040.7 erg/s) [1]
Dimensions131 × 175 pc (430 × 570 ly) [2]
Notable featuresUnusual shape
DesignationsN119, DEM L132, [1] PKS 0518-692, LHA 120-N 119 [3]
See also: Lists of nebulae

N119 (formally known as LHA 120-N 119) is a spiral-shaped H II region in the Large Magellanic Cloud. Its dimensions are large, at 131 x 175 pc (430 × 570 ly). [2] It contains several luminous stars including S Doradus, LH41-1042, and LMC195-1. Its peculiar S-shaped structure is difficult to explain with classical models.

Contents

Location

N119's location within the Large Magellanic Cloud LMC-N119.jpg
N119's location within the Large Magellanic Cloud

With a right ascension of 5h 18m 45s and a declination of −69° 14′ 03″, [1] this nebula may be found in the constellation of Dorado about 160 kly (50 kpc) away. Its apparent size is roughly 9′ 14″ × 12′ 15″. It lies at the northern side of the Large Magellanic Cloud's stellar bar, 15′ southeast of the center of rotation of the galaxy's neutral hydrogen. [2] [4] [5]

Structure

The nebula seems to be in an S-shape, but on closer inspection reveals to have extensions of the spiral arms, ending in a figure 8. [6] The unusual shape may be due to the combination of other nebula, or it may have been formed by perforation of the original molecular cloud by powerful stellar winds and explosions.

It may have also formed by a collision of two interstellar clouds, according to Annie Laval and Patricia Ambrocio-Cruz. The gas would have been compressed, forming the luminous stars seen today. [4]

Bubbles

The N119 nebula with the approximate location of the bubbles marked. N119 nebula.tif
The N119 nebula with the approximate location of the bubbles marked.

N119 contains several bubble-shaped nebulae: DEM L132a; DEM L132b; DEM L123; and an unnamed WR nebula. In total the nebulosity of N119 spans 131 by 175 parsecs (430 ly × 570 ly). [2]

DEM L132a is 88 parsecs across and encompasses the two luminous blue variables S Doradus and R85. However, those stars do not emit sufficient ionising radiation to produce the observed shell, and no other hot luminous stars are seen within the shell. It may have been produced by one or both of the LBVs during an earlier phase of their evolution. DEM L132b is 52 parsecs wide and surrounds two class O giants or supergiants and numerous other hot stars, which comfortably produce the necessary ionising radiation and fast winds to sculpt the bubble from the surrounding interstellar material. The WR bubble nebula is a similar size to DEM L132b and is produced by Brey 21, a binary containing a WN3 star and a B-type supergiant. DEM L123 is 158 parsecs across and its origins are unclear. No sufficiently powerful stars have been detected inside it that could produce it with their stellar wind (as this would require the power of 44 O6 supergiants) and it is ten times too energetic to have originated from a typical supernova. This bubble may have been created by a hypernova. [2]

Bubble NameExciting StarRA of StarDeclination of StarSpectral Type of StarRadius of Bubble
WR Nebula Br 21 05h 18m 19.3s−69° 11′ 41″ WN3 26 pc (84.8 ly)
DEM L123 SNR?---79 pc (257.6 ly)
DEM L132a S Doradus 05h 18m 14.4s−69° 15′ 01″ LBV 44 pc (143.5 ly)
R85 05h 17m 56.1s−69° 16′ 03″ LBV
DEM L132b Sk−69°104 (HDE 269357)05h 18m 59.5s−69° 12′ 55″ O7 III 26 pc (84.8 ly)
LH 41-32 05h 19m 1.9s−69° 13′ 07″ O4 III

Observational history

N119 was first catalogued by Karl Henize, an American Astronomer, when he made a list of Hα emission-line stars and nebulae in 1956. The full designation is LHA 120-N 119: the 119th nebula on Lamont–Hussey Observatory H-alpha (Lamont-Hussey Alpha) plate 120. Plate 120 covered the Large Magellanic Cloud while plate 115 covered the Small Magellanic Cloud. LHA 120-S 119 is a Wolf–Rayet star in another part of the LMC. There is no LHA 115-N 119 since fewer nebulae were found on the SMC plate. [7]

On March 25–26, 1999, The Wide Field Imager, a 67-million pixel digital camera at the MPG/ESO 2.2-m telescope at the La Silla Observatory took a picture of the nebula with a field of view of 31.49 x 30.64 arcminutes at a RA of 5h 18m 37.89s and a declination of −69° 24′ 23.27″, and orientation of north being 1.9° right of vertical. It did four exposures each in the B band (2 minutes each), the V band (2 minutes each), and the Hα band (20 minutes each). [4] It is available for download on ESO's website at 2,303 × 2,241 pixels.

Luminosity

N119 suffers from 0.20 magnitudes of extinction in the B (blue) band, 0.15 in the V (yellow-green) band, and 0.12 in the Hα (red) band. [1]

NGC 1910

N119 has an associated open cluster called NGC 1910 (also known as ESO 56-SC99). Its apparent magnitude is 11.2 and its apparent size is 1.54 arcminutes. It is inside N119 with a right ascension of 5h 18m 42.5s and a declination of −69° 14′ 12.1″. [8]

Notes

  1. ↑ Calculated based on size and distance

Related Research Articles

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<span class="mw-page-title-main">NGC 604</span> H II region inside the Triangulum Galaxy

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<span class="mw-page-title-main">B(e) star</span> B-type star with distinctive forbidden neutral or low ionisation emission lines in its spectrum

A B[e] star, frequently called a B[e]-type star, is a B-type star with distinctive forbidden neutral or low ionisation emission lines in its spectrum. The designation results from combining the spectral class B, the lowercase e denoting emission in the spectral classification system, and the surrounding square brackets signifying forbidden lines. These stars frequently also show strong hydrogen emission lines, but this feature is present in a variety of other stars and is not sufficient to classify a B[e] object. Other observational characteristics include optical linear polarization and often infrared radiation that is much stronger than in ordinary B-class stars, called infrared excess. As the B[e] nature is transient, B[e]-type stars might exhibit a normal B-type spectrum at times, and hitherto normal B-type stars may become B[e]-type stars.

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<span class="mw-page-title-main">NGC 6822</span> Galaxy in the constellation Sagittarius

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<span class="mw-page-title-main">R136b</span> Star in the constellation Dorado

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<span class="mw-page-title-main">R136a1</span> Wolf–Rayet star with one of the highest mass and luminosity of any known star

R136a1 is one of the most massive and luminous stars known, at 196 M☉ and nearly 4.7 million L☉, and is also one of the hottest, at around 46,000 K. It is a Wolf–Rayet star at the center of R136, the central concentration of stars of the large NGC 2070 open cluster in the Tarantula Nebula in the Large Magellanic Cloud. The cluster can be seen in the far southern celestial hemisphere with binoculars or a small telescope, at magnitude 7.25. R136a1 itself is 100 times fainter than the cluster and can only be resolved using speckle interferometry.

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<span class="mw-page-title-main">N44 (emission nebula)</span> Emission nebula in the constellation Dorado

N44 is an emission nebula with superbubble structure located in the Large Magellanic Cloud, a satellite galaxy of the Milky Way in the constellation Dorado. Originally catalogued in Karl Henize's "Catalogue of H-alpha emission stars and nebulae in the Magellanic Clouds" of 1956, it is approximately 1,000 light-years wide and 160,000-170,000 light-years distant. N44 has a smaller bubble structure inside known as N44F. The superbubble structure of N44 itself is shaped by the radiation pressure of a 40-star group located near its center; the stars are blue-white, very luminous, and incredibly powerful. N44F has been shaped in a similar manner; it has a hot, massive central star with an unusually powerful stellar wind that moves at 7 million kilometers per hour. This is because it loses material at 100 million times the rate of the Sun, or approximately 1,000,000,000,000,000 tons per year. However, varying density in the N44 nebula has caused the formation of several dust pillars that may conceal star formation. This variable density is likely caused by previous supernovae in the vicinity of N44; many of the stars that have shaped it will eventually also end as supernovae. The past effects of supernovae are also confirmed by the fact that N44 emits x-rays.

<span class="mw-page-title-main">R136a2</span> Star in the constellation Dorado

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<span class="mw-page-title-main">WR 31a</span> Wolf Rayet star in the constellation Carina

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<span class="mw-page-title-main">NGC 1910</span> Star cluster in the constellation Dorado

NGC 1910, or LH-41, is an OB association in the Large Magellanic Cloud.

<span class="mw-page-title-main">R85</span> Candidate luminous variable star in the constellation Dorado

R85 is a candidate luminous blue variable located in the LH-41 OB association in the Large Magellanic Cloud.

<span class="mw-page-title-main">Sh2-308</span> Emission nebula

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<span class="mw-page-title-main">R71 (star)</span> Star in the Large Magellanic Cloud

R71 is a star in the Large Magellanic Cloud (LMC) in the constellation Mensa. It is classified as a luminous blue variable and is one of the most luminous stars in the LMC. It lies three arc-minutes southwest of the naked-eye star β Mensae.

<span class="mw-page-title-main">LHA 120-N 55</span> Nebula in the constellation Dorado

LHA 120-N 55 or N55 is an emission nebula located within the Large Magellanic Cloud (LMC). N55 is situated inside a superbubble called LMC 4. It is a glowing clump of gas and dust that gets its light output from the hydrogen atoms shedding electrons within it. It was named in 1956, in a catalogue of H-alpha emission line objects in the LMC.

<span class="mw-page-title-main">N41 (nebula)</span> Nebula in the constellation Dorado

N41 is an emission nebula in the north part of the Large Magellanic Cloud in the Dorado constellation. Originally catalogued in Karl Henize's "Catalogue of H-alpha emission stars and nebulae in the Magellanic Clouds" of 1956, it is approximately 100 light-years wide and 160,000-170,000 light-years distant.

<span class="mw-page-title-main">Henize 70</span> H II region in the Large Magellanic Cloud

Henize 70 (N70) is a faint emission nebula and superbubble located in the Large Magellanic Cloud. It is located in the constellation of Dorado.

References

  1. 1 2 3 4 5 6 Lopez, Laura A.; Krumholz, Mark R.; Bolatto, Alberto D.; Prochaska, J. Xavier; Ramirez-Ruiz, Enrico; Castro, Daniel (2014). "The Role of Stellar Feedback in the Dynamics of H II Regions". The Astrophysical Journal. 795 (2): 121. arXiv: 1309.5421 . Bibcode:2014ApJ...795..121L. doi:10.1088/0004-637X/795/2/121. S2CID   13365680.
  2. 1 2 3 4 5 6 Ambrocio-Cruz, P.; Rosado, M.; Laval, A.; Le Coarer, E.; Russeil, D.; Amram, P. (July 22, 2008). "Kinematic field of the S-shaped nebula N119 in the LMC" (PDF). Revista Mexicana de Astronomía y Astrofísica. 44: 355. Bibcode:2008RMxAA..44..355A.
  3. ↑ "LHA 120-N 119". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 17 November 2016.
  4. 1 2 3 "Beautiful Nebulae in the Large Magellanic Cloud". ESO. Retrieved November 19, 2016.
  5. ↑ "The View from La Silla". Scientific American. Retrieved August 5, 2018.
  6. ↑ Exploring The Southern Sky. Springer Science & Business Media. December 6, 2012. p. 53. ISBN   978-3-642-64877-9.
  7. ↑ Henize, Karl G. (May 5, 1956). "Catalogues of Hα-emission Stars and Nebulae in the Magellanic Clouds". Astrophysical Journal Supplement. 2: 35. Bibcode:1956ApJS....2..315H. doi:10.1086/190025.
  8. ↑ "NGC 1910". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 20 November 2016.
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