Search results
Results from the WOW.Com Content Network
A G-type main-sequence star (spectral type: G-V), also often, and imprecisely, called a yellow dwarf, or G star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temperature between about 5,300 and 6,000 K (5,000 and 5,700 °C ; 9,100 and 10,000 °F ).
The Sun is a G-type main-sequence star (G2V), informally called a yellow dwarf, though its light is actually white. It formed approximately 4.6 billion [a] years ago from the gravitational collapse of matter within a region of a large molecular cloud.
Yellow dwarf stars correspond to the G-class stars of the main sequence, with a mass between 0.9 and 1.1 M☉, [2] and surface temperatures between 5000 and 6000 K. [3] Since the Sun itself is a yellow dwarf, of type G2V, [11] these types of stars are also known as solar analogs.
Excluding colour-contrast effects in dim light, in typical viewing conditions there are no green, cyan, indigo, or violet stars. "Yellow" dwarfs such as the Sun are white, "red" dwarfs are a deep shade of yellow/orange, and "brown" dwarfs do not literally appear brown, but hypothetically would appear dim red or grey/black to a nearby observer.
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) [2] 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.
These stars are intermediate in size between red M-type main-sequence stars ("red dwarfs") and yellow/white G-type main-sequence stars. They have masses between 0.6 and 0.9 times the mass of the Sun and surface temperatures between 3,900 and 5,300 K . [ 1 ]
Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole.
This temperature range gives the F-type stars a whitish hue when observed by the atmosphere. Because a main-sequence star is referred to as a dwarf star, this class of star may also be termed a yellow-white dwarf (not to be confused with white dwarfs, remnant stars that are a possible final stage of stellar evolution).