NGC 3603 is a nebula situated in the

Carina–Sagittarius Arm The Carina–Sagittarius Arm (also known as the Sagittarius Arm or Sagittarius–Carina Arm, labeled -I) is generally thought to be a minor spiral arm of the Milky Way galaxy. Each spiral arm is a long, diffuse curving streamer of stars that ra ...

of the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

around 20,000 light-years away from the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

. It is a massive

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 ...

containing a very compact

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, an ...

(probably a super star cluster)

HD 97950 HD 97950, is a multiple star system and part of a super star cluster within the NGC 3603 H II region. It was catalogued as a single star although it was always known to be a compact cluster. It is now resolved into a massive multiple star at th ...

Observations

NGC 3603 was observed by John Herschel on 14 March 1834 during his visit to South Africa, who remarked that it was "a very remarkable object...perhaps a

globular cluster A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...

". Herschel catalogued it as nebula 3334 in his ''Results of Astronomical Observations made at the Cape of Good Hope'', published in 1847. In 1864 the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

published his ''

General Catalogue of Nebulae and Clusters A general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel."general, adj. and n.". OED On ...

'', where he listed it as number 2354. It was subsequently incorporated into the '' New General Catalogue'' as by J. L. E. Dreyer as NGC 3603. The central cluster was catalogued as the star

, but has long been recognised as nebulous or multiple. It was also noted for having an unusual emission spectrum and the spectral type was given as Oe in the Henry Draper Catalogue. This was later refined to WN5 + O as the emission was recognised as characteristic of a

Wolf–Rayet star Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very high surface ...

. Eventually, the cluster would be resolved and found to contain three of the most massive and most luminous stars known, as well as a number of luminous O class stars and many fainter stars.

Features

NGC 3603 is the most massive visible cloud of glowing

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

and plasma, known as a

, in the Milky Way. The central star cluster is the densest concentration of very massive stars known in the galaxy. Strong

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...

radiation and stellar winds have cleared the gas and dust, giving an unobscured view of the cluster. Three prominent

Wolf–Rayet stars Wolf–Rayet (WR) can mean: * Wolf–Rayet star, a type of evolved, massive star * Wolf–Rayet galaxy, which contains large numbers of Wolf–Rayet stars * Wolf–Rayet nebula A Wolf–Rayet nebula is a nebula which surrounds a Wolf–Rayet st ...

have been detected within the cluster, all originally unresolved and known as the single star HD 97950. The brightest of the three, HD 97950A1 (or NGC 3603-A1) is actually a

pair Pair or PAIR or Pairing may refer to: Government and politics * Pair (parliamentary convention), matching of members unable to attend, so as not to change the voting margin * ''Pair'', a member of the Prussian House of Lords * ''Pair'', the Frenc ...

of Wolf–Rayet stars that orbit around each other once every 3.77 days. The primary is an estimated mass , while its companion is . The star designated HD 97950B is a single star more massive and more luminous than either of the individual members of HD 97950A1. It is 2,880,000 times as luminous as the sun and 132 times as massive. NGC 3603 is visible in the telescope as a small rather insignificant nebulosity with a yellowish tinge due to the effects of interstellar absorption. In the mid-1960s, optical studies combined with radio astronomical observations showed it to be an extremely strong thermal radio source. Later observations of other galaxies introduced the concept of

starburst region A starburst is an astrophysical process that involves star formation occurring at a rate that is large compared to the rate that is typically observed. This starburst activity will consume the available interstellar gas supply over a timespan that ...

s, in some cases whole galaxies, of extremely rapid star formation. NGC 3603 is now considered to be such a region, and it has been compared by some authors to the larger cluster

30 Doradus The Tarantula Nebula (also known as 30 Doradus) is a large H II region in the Large Magellanic Cloud (LMC), forming its south-east corner (from Earth's perspective). Discovery The Tarantula Nebula was observed by Nicolas-Louis de Lacaille durin ...

, in the Large Magellanic Cloud.

Sher 25 Sher 25 is a blue supergiant star in the constellation Carina, located approximately 25,000 light years from the Sun in the H II region NGC 3603 of the Milky Way. It is a spectral type B1Iab star with an apparent magnitude of 12.2. ...

, the B class supergiant on the outskirts of NGC 3603, is surrounded by ejected material in an hourglass shape similar to that found for the supernova 1987A, and this has aroused intense interest in the future evolution of stars such as Sher 25. Two of the most luminous young stars known are found within NGC 3603, but outside the central cluster.

WR 42e WR 42e (2MASS J11144550-115001) is a Wolf–Rayet star in the massive H II region NGC 3603 in the constellation of the Carina. It is around 25,000 light-years or 7,600 parsec from the Sun. WR 42e is one of the most massive and most lumin ...

and NGC 3603 MTT 58 both have a spectral type of O2If*/WN6 indicating an extremely massive young star. WR 42e is a possible runaway from a three-body encounter, while MTT 58 appears to still be embedded within its parental cocoon and is in a possible binary with an O3If star.

References

External links

Hubble Space Telescope: Star Cluster Bursts into Life in New Hubble Image

European Southern Observatory: The Stars behind the Curtain
{{DEFAULTSORT:Ngc 3603 Carina (constellation) H II regions 3603 Star-forming regions