The effective temperature of a star is the temperature of a black body with the same luminosity (L) as the star and is defined according to the Stefan-Boltzman law L = sigma T_{eff}^{4}. The effective temperature of our Sun is around 5,800 kelvins (K) and correspond to the temperature on the surface of the star. The definition of the stellar surface is obviously not straightforward and more rigorously the effective temperature correspond to the temperature at the Rosselan optical depth. As the temperature decreases, the peak of the black body radiation curve moves to lower intensities and longer wavelengths. ... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero—the lowest possible temperature where nothing could be colder and no heat energy remains in a substance—is defined as zero kelvin (0 K). ...

Stars actually have a temperature gradient, going from the core up to their atmospheres. The "core temperature" of the sun, i.e. the temperature at the centre of the sun, is estimated to be 15,000,000 K.

The color of a star indicates its temperature along a spectrum from the very cool (by stellar standards, that is) red M stars that radiate heavily in the infrared to the very blue O stars that radiate largely in the ultraviolet. The effective temperature of a star indicates the amount of heat that the star radiates per unit of surface area. From the warmest surfaces to the coolest is the sequence of star types known as O, B, A, F, G, K, and M. Color is an important part of the visual arts. ... Image of two girls in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... The solar corona as seen in deep ultraviolet light at 17. ...

A red star could be a tiny red dwarf, a star of feeble energy production and a small surface or a bloated giant or even supergiant star such as Antares or Betelgeuse, either of which generates far greater energy but passes it through a surface so large that the star radiates little per unit of surface area. A star near the middle of the spectrum, such as the modest Sun or the giant Capella radiates more heat per unit of surface area than the feeble red dwarf stars or the bloated supergiants, but much less than such a white or blue star as Vega or Rigel. Red Dwarf is a British science fiction sitcom that has so far run for eight series between 1988 and 1999. ... Supergiants are the most massive stars. ... This article or section does not cite its references or sources. ... Betelgeuse (Alpha (α) Orionis) (also written Betelguese and Betelgeux) is a semiregular variable star located 427 light-years away [1]. It is the second brightest star in the constellation Orion, and the ninth brightest star in the night sky. ... For other uses, see Sun (disambiguation). ... The term capella can refer to: A cappella, a music term referring to vocal music or singing without instrumental accompaniment. ... Vega (α Lyr / α Lyrae / Alpha Lyrae) is a white main sequence star approximately 25. ... Rigel (pronounced ) (β Orionis) is the brightest star in the constellation Orion and the seventh brightest star in the sky, with visual magnitude 0. ...