Search results
Results from the WOW.Com Content Network
Main-sequence stars vary in surface temperature from approximately 2,000 to 50,000 K, whereas more-evolved stars – in particular, newly-formed white dwarfs – can have surface temperatures above 100,000 K. [3] Physically, the classes indicate the temperature of the star's atmosphere and are normally listed from hottest to coldest.
The color-color diagram of stars can be used to directly calibrate or to test colors and magnitudes in optical and infrared imaging data. Such methods take advantage of the fundamental distribution of stellar colors in our galaxy across the vast majority of the sky, and the fact that observed stellar colors (unlike apparent magnitudes ) are ...
Main-sequence stars are called dwarf stars, [19] [20] but this terminology is partly historical and can be somewhat confusing. For the cooler stars, dwarfs such as red dwarfs , orange dwarfs , and yellow dwarfs are indeed much smaller and dimmer than other stars of those colors.
Because these stars would have been "brighter" in the past, the color of the universe changes over time, shifting from blue to red as more blue stars change to yellow and eventually red giants. As light from distant galaxies reaches the Earth, the average "color of the universe" (as seen from Earth) tends towards pure white, due to the light ...
Rigel and the IC 2118 nebula which it illuminates.. It was once believed that blue supergiants originated from a "feeding" with the interstellar medium when stars passed through interstellar dust clouds, [11] [8] although the current consensus is that blue supergiants are evolved high-mass stars, a natural consequence of stellar evolution, larger and more luminous than main-sequence stars.
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 color of a star, as determined by the most intense frequency of the visible light, depends on the temperature of the star's outer layers, including its photosphere. [176] Besides visible light, stars emit forms of electromagnetic radiation that are invisible to the human eye .
In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. The lower the color index, the more blue (or hotter) the object is. Conversely, the larger the color index, the more red (or cooler) the object is.