- subdwarf
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A star that is dimmer than a main sequence star of same temperature. They are located below the main sequence in the Hertzsprung-Russell diagram.Syn: subdwarf star
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subdwarf
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Subdwarf star — A subdwarf star, sometimes denoted by sd , is luminosity class VI under the Yerkes spectral classification system. They are defined as stars with luminosity 1.5 to 2 magnitudes lower than that of main sequence stars of the same spectral type. On… … Wikipedia
Subdwarf B star — The subdwarf B star is a kind of subdwarf star with spectral type B. They are from the extreme horizontal branch stars of the Hertzsprung Russell diagram. These stars represent a late stage in the evolution of some stars, caused when a red giant… … Wikipedia
subdwarf star — sub|dwarf «SUHB DWRF», noun, or subdwarf star, any star of a group lying just below the main sequence in the Russell diagram, being relatively small and dim when compared to a mainsequence star of the same spectral class … Useful english dictionary
subdwarf — noun Date: 1939 a small hot star containing few elements heavier than helium and having lower luminosity than a main sequence star of similar temperature … New Collegiate Dictionary
subdwarf — sub·dwarf … English syllables
subdwarf — ˈsəb+ˌ noun Etymology: sub + dwarf : a star having higher surface temperature for its mass and luminosity than is usual to stars of the main sequence and therefore having relatively high density and lying to the left of the main sequence on the… … Useful english dictionary
Stellar classification — In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are… … Wikipedia
White dwarf — For other uses, see White dwarf (disambiguation). Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint pinprick of light to the lower left of the much brighter Sirius A … Wikipedia
Compact star — In astronomy, the term compact star (sometimes compact object) is used to refer collectively to white dwarfs, neutron stars, other exotic dense stars, and black holes. These objects are all small for their mass. The term compact star is often… … Wikipedia
Dwarf star — The term dwarf star refers to a variety of distinct classes of stars. Dwarf star alone generally refers to any main sequence star, a star of luminosity class V. Red dwarfs are low mass main sequence stars. Yellow dwarfs are main sequence (dwarf)… … Wikipedia
