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    • Source: Dwarf star

      • A dwarf star is a star of relatively small size and low luminosity. Most main sequence stars are dwarf stars. The meaning of the word "dwarf" was later extended to some star-sized objects that are not stars, and compact stellar remnants that are no longer stars.


      History


      The term was originally coined in 1906 when the Danish astronomer Ejnar Hertzsprung noticed that the reddest stars – classified as K and M in the Harvard scheme – could be divided into two distinct groups. They are either much brighter than the Sun, or much fainter. To distinguish these groups, he called them "giant" and "dwarf" stars, the dwarf stars being fainter and the giants being brighter than the Sun.
      Most stars are currently classified under the Morgan Keenan System using the letters O, B, A, F, G, K, and M, a sequence from the hottest: type O, to the coolest: type M.
      With the development of infrared astronomy in the late 20th century the Morgan Keenan system was extended to cooler types L and T, all of which are "dwarfs" but not all of which are stars as such.


      Current uses of the term "dwarf"



      The scope of the term "dwarf" at present includes the following:

      Dwarf star with no other qualification generally refers to a main-sequence star, a star of luminosity class V: main-sequence stars (dwarfs). Example: Achernar (B6Vep)
      Red dwarfs are low-mass main-sequence stars.
      Yellow dwarfs are main-sequence (dwarf) stars with masses comparable to that of the Sun.
      Orange dwarfs are K-type main-sequence stars.
      Blue (type O and type B) main sequence stars are so large that they are difficult to distinguish from blue giant stars, either in size or brightness, and because of the cognitive dissonance, the word "dwarf" is avoided when referring to them.
      A blue dwarf is a hypothesized class of very-low-mass stars that increase in temperature as they near the end of their main-sequence lifetime. (It is believed that the universe is not old enough for any red dwarf to have yet reached the so-called "blue" stage, which is actually more of a medium white.
      A white dwarf is the remains of a dead star, composed of electron-degenerate matter. It is thought to be the final stage in the evolution of stars not massive enough to collapse into a neutron star or black hole – stars less massive than roughly 9 M☉.
      A black dwarf is theorized as a white dwarf that has cooled sufficiently that it no longer emits any visible light. It is believed that the universe is not old enough for any white dwarf to have yet cooled to "black".
      A brown dwarf is a substellar object not massive enough to ever fuse hydrogen into helium, but still massive enough to fuse deuterium – less than about 0.08 M☉ and more than about 13 Jupiter masses.


      See also


      Chandrasekhar limit
      Dwarf planet
      Stellar classification
      Sub-brown dwarf
      Subdwarf
      Ultra-cool dwarf


      References

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    Artikel Terkait "dwarf star"

    Dwarf star - Wikipedia

    A dwarf star is a star of relatively small size and low luminosity. Most main sequence stars are dwarf stars. The meaning of the word "dwarf" was later extended to some star-sized objects that are not stars, and compact stellar remnants that are no longer stars.

    Dwarf star | Red Dwarf, Neutron Star & White Dwarf | Britannica

    dwarf star, any star of average or low luminosity, mass, and size. Important subclasses of dwarf stars are white dwarfs (see white dwarf star) and red dwarfs. Dwarf stars include so-called main-sequence stars, among which is the Sun.

    Dwarf Star: Types, Characteristics, and More Exciting Features

    What is a Dwarf Star? The term “dwarf star” was created by Ejnar Hertzsprung in 1906. He used it to distinguish prominent K and M-type stars that are either brighter or dimmer than the Sun. Those that are bigger and much brighter are called “giant …

    Red dwarf star | Definition, Facts, & Temperature | Britannica

    07 Jan 2025 · Red dwarfs are the coolest main-sequence stars, with a spectral type of M and a surface temperature of about 2,000–3,500 K. Because these stars are so cool, spectral lines of …

    Star Types - Science@NASA

    22 Okt 2024 · Red dwarfs are the smallest main sequence stars – just a fraction of the Sun’s size and mass. They’re also the coolest, and appear more orange in color than red.

    White dwarf star | Definition, Size, Mass, Life Cycles, & Facts ...

    16 Jan 2025 · White dwarf star, any of a class of faint stars representing the endpoint of the evolution of intermediate- and low-mass stars. White dwarf stars are characterized by a low luminosity, a mass on the order of that of the Sun, and a radius comparable to that of Earth.

    What is a Dwarf Star? – All The Stars We Cannot See

    A “dwarf star” is a term used to describe any star that is smaller, cooler, and less luminous than main-sequence stars like our Sun. The classification of a star as a dwarf doesn’t necessarily imply its size or mass but rather its stage in the stellar evolution process or its characteristics on the Hertzsprung-Russell diagram.

    Stars come in a variety of sizes - NASA Solar System …

    The most massive stars that can still be called dwarf stars are stars with about six to eight solar masses. Their luminosities, or brightnesses, are about 100 times that of the sun, and they use up the hydrogen fuel in their cores in only 100 million years.

    Ultra-massive white dwarf reveals 19 pulsation modes, a new record

    5 days ago · Using the Gran Telescopio Canarias (GTC) and the Apache Point Observatory (APO), an international team of astronomers has detected 19 pulsation modes in an ultra-massive white dwarf known as WD ...

    Dwarf star - Simple English Wikipedia, the free encyclopedia

    Dwarf stars refers to several types of star. The term was originally used in 1906 by the Danish astronomer Ejnar Hertzsprung. He noticed that the reddest stars—classified as K and M in the Harvard scheme—could be divided into two distinct groups. They are either much brighter than the Sun, or much fainter.