N119 (formally known as LHA 120-N 119) is a spiral-shaped

H II region An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds ...

in the

Large Magellanic Cloud The Large Magellanic Cloud (LMC), or Nubecula Major, is a satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (≈160,000 light-years), the LMC is the second- or third-closest galaxy to the Milky Way, after the ...

. Its dimensions are large, at 131 x 175 pc (430 × 570 ly). It contains several luminous stars including

S Doradus S Doradus (also known as S Dor) is one of the brightest stars in the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way, located roughly 160,000 light-years away. The star is a luminous blue variable, and one of the ...

LH41-1042 LH 41-1042 is a Wolf–Rayet star located in the Large Magellanic Cloud (LMC). It is an extremely rare member of the Wolf–Rayet star, WO oxygen sequence, the second to be discovered in the LMC and one of only three found so far in that ...

, and

LMC195-1 LMC195-1 is a Wolf–Rayet star located in the Large Magellanic Cloud (LMC). It is an extremely rare member of the WO oxygen sequence, at WO2 the hottest known in the LMC. It is likely to be one of the hottest stars known. The star wa ...

. Its peculiar S-shaped structure is difficult to explain with classical models.

Location

With a

right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth. When paired w ...

of and a

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

of , this nebula may be found in the constellation of

Dorado Dorado () is a constellation in the southern sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish (''Coryphaena hippurus''), which is known as ''dorado'' in Spanish, altho ...

about 160 kly (50 kpc) away. Its apparent size is roughly 9′ 14″ × 12′ 15″. It lies at the northern side of the

's stellar bar, 15′ southeast of the center of rotation of the galaxy's

neutral hydrogen The hydrogen line, 21 centimeter line, or H I line is the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation has a precise frequency of , w ...

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. 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.

Bubbles

N119 contains several bubble-shaped nebulae: DEM L132a; DEM L132b; DEM L123; and an unnamed WR nebula. In total the nebulosity of N119 spans . DEM L132a is 88 parsecs across and encompasses the two

luminous blue variable Luminous blue variables (LBVs) are massive evolved stars that show unpredictable and sometimes dramatic variations in their spectra and brightness. They are also known as S Doradus variables after S Doradus, one of the brightest stars of the Larg ...

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 Brey may refer to: People * August Brey (1864–1937), German politician * Betty Brey (1931–2015), American swimmer * Carol A. Brey-Casiano, American librarian * Carter Brey (born 1954), American cellist * Claire Du Brey (1892–1993), American ...

, 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 A stellar wind is a flow of gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric. D ...

(as this would require the power of 44 O6 supergiants) and it is ten times too energetic to have originated from a typical

supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...

. This bubble may have been created by a

hypernova A hypernova (sometimes called a collapsar) is a very energetic supernova thought to result from an extreme core-collapse scenario. In this case, a massive star (>30 solar masses) collapses to form a rotating black hole emitting twin energetic je ...

Observational history

N119 was first catalogued by

Karl Henize Karl Gordon Henize (;JPL-80 "NASA Creates Portrait of Life and ...

, an American Astronomer, when he made a list of H_α

emission-line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission (electromagnetic radiation), emission or absorption (electromagnetic radiation), absorption of light in a narrow frequency range, ...

stars and nebulae in 1956. The full designation is LHA 120-N 119: the 119th nebula on

Lamont–Hussey Observatory The Lamont–Hussey Observatory (LHO) was an astronomical observatory owned and operated by the University of Michigan (UM). It was located in the city of Bloemfontein, Free State, South Africa. Construction at the site began in 1927, and the f ...

H-alpha H-alpha (Hα) is a specific deep-red visible spectral line in the Balmer series with a wavelength of 656.28 nm in air and 656.46 nm in vacuum; it occurs when a hydrogen electron falls from its third to second lowest energy level. H-alph ...

(Lamont-Hussey Alpha) plate 120. Plate 120 covered the Large Magellanic Cloud while plate 115 covered the

Small Magellanic Cloud The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about , and contains several hundred million stars. It has a total mass of ...

. 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. 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 La Silla Observatory is an astronomy, astronomical observatory in Chile with three telescopes built and operated by the European Southern Observatory (ESO). Several other telescopes are located at the site and are partly maintained by ESO. The obse ...

took a picture of the nebula with a field of view of 31.49 x 30.64 arcminutes at a RA of and a declination of , 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 H_α band (20 minutes each). It is available for download on

ESO The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental research organisation made up of 16 member states for ground-based ast ...

's website at 2,303 × 2,241 pixels.

Luminosity

N119 suffers from 0.20 magnitudes of

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

in the B (blue) band, 0.15 in the V (yellow-green) band, and 0.12 in the H_α (red) band.

NGC 1910

N119 has an associated

open cluster An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

called

NGC 1910 NGC 1910, or LH-41, is an OB association in the Large Magellanic Cloud. Location NGC 1910's right ascension is and its declination is -69° 14′ 12.1″. Its angular size is 1.54 arcminutes. N119 The cluster has an associated HII regi ...

(also known as ESO 56-SC99). Its

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

is 11.2 and its

apparent size The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ...

is 1.54

arcminutes A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...

. It is inside N119 with a

of and a

of .

Notes

References

External links

Original image
{{DEFAULTSORT:N119 H II regions Dorado (constellation) Large Magellanic Cloud Star-forming regions