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Starburst article OC:
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A starburst is an astrophysical event which involves star formation occurring at a rate that is large compared to the rate that is normally observed. A starburst will consume the gas supply in a timespan that is much shorter than the lifetime of the galaxy. For example NGC 6334 has a star formation rate estimated to be 3600 Solar Masses per year[1] while the star formation rate of the Milky Way is only about seven solar masses per year.[2] Due to the high amount of star formation a starburst is usually accompanied by much higher gas pressure and a larger ratio of HCN to CO emission lines than are usually observed.[3]
Starburst can occur in entire galaxies or just regions of space. A starburst region is a region of space that is undergoing a large amount of star formation. For example the Tarantula Nebula is a Nebula in the Large Magellanic Cloud which has one of the highest star formation rates in the Local Group[4]. By contrast a starburst galaxy is an entire galaxy that is experiencing a very high star formation rate. One notable example being Messier 82 in which the gas pressure is 100 times greater than in the local neighborhood and it is forming stars at about the same rate as the Milky Way in a region about 600 parsecs across.[3] At this rate M82 will consume its 200 million Solar Masses of atomic and molecular hydrogen in 100 Mega years (its Free-fall time)[3].
Starburst regions can occur in different shapes, for example in Messier 94 the inner ring is a star burst region[5]. Messier 82 has a starburst core of about 600 parsec in diameter[3]. Starbursts are common during galaxy mergers such as the Antennae Galaxies. In the case of mergers the starburst can either be local or galaxy wide depending on the galaxies and how they are merging.
References
edit- ^ "NGC 6334 - A Mini Starburst Region | Department of Physics & Astronomy". www.physastro.iastate.edu. Retrieved 2016-10-10.
- ^ Robitaille, Thomas; Whitney, Barbara (2010). "The present-day star formation rate of the Milky-Way determined from Spitzer detected young stellar objects". arXiv:1001.3672.
- ^ a b c d Sparke, Linda; Gallagher III, John (2007). Galaxies in the Universe. New York: Cambridge University Press. p. 289. ISBN 978-0-521-67186-6.
- ^ Lebouteiller, V.; Bernard-Salas, J.; Brandl, B.; Whelan, D. G.; Wu, Y.; Charmandaris, V.; Devost, D.; Houck, J. R. (2008-06-10). "Chemical composition and mixing in giant HII regions: NGC3603, 30Doradus, and N66". The Astrophysical Journal. 680 (1): 398–419. doi:10.1086/587503. ISSN 0004-637X.
- ^ C. Muñoz-Tuñón; N. Caon; J. Aguerri; L. Alfonso (2004). "The Inner Ring of NGC 4736: Star Formation on a Resonant Pattern". Astronomical Journal. 127 (1): 58–74. Bibcode:2004AJ....127...58M. doi:10.1086/380610.