protostars
toʊˌstɑr
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2013.
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Based on the Random House Dictionary, © Random House, Inc. 2013.
Cite This Source
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Link To Protostars
Collins
World English Dictionary
protostar (ˈprəʊtəʊˌstɑː) ![[Click for IPA pronunciation guide]](http://static.sfdict.com/dictstatic/g/d/dictionary_questionbutton_default.gif) | |
| —n | |
| a cloud of interstellar gas and dust that gradually collapses, forming a hot dense core, and evolves into a star once nuclear fusion can occur in the core | |
Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
00:10
Protostars
is always a great word to know.
So is quincunx. Does it mean:
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
American Heritage
Science Dictionary
protostar  (prō'tə-stär') Pronunciation Key
A celestial object made of a contracting cloud of interstellar medium (mostly hydrogen gas) that eventually becomes a main-sequence star. Disturbances in some region of interstellar medium can cause fluctuations of density through that region, and the denser areas, having more mass, begin to attract more and more of the medium through the force of gravity (a process known as accretion). Ever increasing densities of such protostar regions lead to ever higher temperatures within the accreting body, until the point is reached when thermal energy is sufficient to promote the fusion reactions typical of main-sequence stars. Less massive protostars may take hundreds of millions of years to evolve into stars; massive ones contract more quickly and may take only a few hundred thousand years. |
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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