单词 | white dwarf |
释义 | white dwarfnoun Astronomy.a star, approximately the size of the earth, that has undergone gravitational collapse and is in the final stage of evolution for low-mass stars, beginning hot and white and ending cold and dark (black dwarf ). Compare Chandrasekhar limit. Origin of white dwarfFirst recorded in 1920–25 Words nearby white dwarfwhite currant, whited, white damp, whited sepulcher, whited sepulchre, white dwarf, white elephant, white ensign, white-eye, white-eyed vireo, whiteface Dictionary.com UnabridgedBased on the Random House Unabridged Dictionary, © Random House, Inc. 2020 British Dictionary definitions for white dwarfwhite dwarf nounone of a large class of small faint stars of enormous density (on average 10 8 kg/m³) with diameters only about 1 per cent that of the sun, and masses less than the Chandrasekhar limit (about 1.4 solar masses). It is thought to mark the final stage in the evolution of a sun-like star Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cultural definitions for white dwarfwhite dwarf A kind of star about the size of the Earth. White dwarfs represent a final stage of the life cycle of stars similar to the sun; they are formed when the stars use up their fuel and can no longer support nuclear reactions. The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved. Scientific definitions for white dwarfwhite dwarf A small, extremely dense star characterized by high temperature and luminosity. A white dwarf is believed to be in its final stage of evolution, having either used up most of its nuclear fuel in its main-sequence stage, or else moved through a giant stage and shed any remaining fuel in its outer layer as a planetary nebula, leaving only a glowing core. Some 10 percent of all stars in the Milky Way are white dwarfs, but despite their intrinsic luminosity, they are so small that none are visible to the naked eye. See Note at dwarf. The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved. |
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