HST image of NGC 3603
|Observation data (J2000 epoch)|
|Right ascension||11h 15m 09.1s|
|Declination||-61° 16′ 17″|
|Distance||20 kly (7.6 kpc )|
|Apparent magnitude (V)||9.1|
|Apparent dimensions (V)||3′|
|Notable features||Central region is the young cluster HD 97950|
It was observed by John Herschel on the 14th of March 1834 during his visit to South Africa, who remarked that it was "a very remarkable object...perhaps a globular cluster". 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 published his General Catalogue of Nebulae and Clusters, 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.
It is surrounded by the most massive visible cloud of glowing gas and plasma known as a H II region in the Milky Way. HD 97950 is the central star of star cluster, the densest concentration of very massive stars known in the galaxy. Strong ultraviolet radiation and stellar winds have cleared the gas and dust, giving an unobscured view of the cluster.
Three prominent Wolf-Rayet stars have been detected within the cluster. These three massive stars have been observed and their solar mass measured using the Very Large Telescope. The largest of the three, NGC 3603-A1 is a blue double star that orbit around each other once every 3.77 days. The two combined have a solar mass that is 200 times more massive than our Sun: (A1-a) is the largest known star in our galaxy with an estimated mass of 116 solar masses, while its companion (A1-b) has a mass of 89 solar masses.
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 coincided with radio astronomical observations which showed it to be an extremely strong thermal radio source. Later observations in other galaxies introduced the concept of 'starburst' regions, in some cases whole galaxies, of extremely rapid star formation and NGC 3603 is now considered to be such a region.
In 1987 a supernova (known as SN 1987A) occurred in the Large Magellanic Cloud. This was the first supernova to be close enough for detailed observation with satellite based telescopes. One result was the discovery that prior to the main explosion it had thrown off a relatively small amount of material in a very distinctive pattern, a bit like an hourglass perpendicular to a detached glowing ring. One star in NGC 3603 (Sher 25, the number comes from the 1960s optical observations) was found to have thrown off matter in a pattern similar to that found for the supernova 1987A. This coincidence has aroused intense interest.
Recent discovery 
Nine objects have been observed in J and H bands that exhibit brown dwarf-like features but are too luminous for the distance it is in the cluster. The objects are being proposed as field brown dwarfs (in front of the cluster) or stars that have recently swallowed a planet.
- "SIMBAD Astronomical Database". Results for NGC 3603. Retrieved 2006-11-28.
- "Star Cluster Bursts into Life in New Hubble Image - Fast Facts". Retrieved 2007-10-07.
- The Massive Star Content of NGC 3603, Melena et al. (2008)
- Harayama,Yohei: The IMF of the massive star-forming region NGC 3603 from NIR adaptive optics observations, Ludwig Maximilian University of Munich, January 2007, p.11-12
- Sher, D. (1965). "The Curious History of NGC 3603". Journal of the Royal Astronomical Society of Canada 59: 67–70. Bibcode:1965JRASC..59...67S.
- B. Brandl, W. Brandner, E.K. Grebel AND H. Zinnecker: "VLT/ISAAC and HST/WFPC2 Observations of NGC 3603", (The Messenger, No. 98 – December 1999, European Organisation for Astronomical Research in the Southern Hemisphere, Garching, Germany)
- KH Hofmann, G Weigelt, W Seggewise: "Resolution and evolution of the core of the giant HII region NGC 3603"(Symposium-International Astronomical Union, 1995)
- Drissen, L., Moffat, A.F.J., Walborn, N.R. and Shara, M.M. The dense galactic starburst NGC 3603. I. HST/FOS spectroscopy of individual stars in the core (Astronomical Journal v.110, p.2235)
- C. G. De Pree, Melissa C. Nysewander, & W. M. Goss: NGC 3576 and NGC 3603: Two Luminous Southern H Ii Regions Observed At High Resolution With The Australia Telescope Compact Array, Astronomical Journal, University of Chicago Press, June 1999, Vol. 117, p.2916
- Bates, Claire: Pictured: The cosmic factory that created the largest known star in our galaxy, Daily Mail, London, 4 February 2010 
- Detection of brown dwarf-like objects in the core of NGC3603, Loredana Spezzi, et.al
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