STELLAR RADIATION AND TEMPERATURE

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[...] The mass lost in the reaction is equivalent to an energy: So we therefore 2ème partie: radiation of stars and their temperature LIGHT, AN ELECTROMAGNETIC RADIATION In 1666 (1717th in the 17th century), Isaac Newton discovered that light could be decomposed into several colored lights. Electromagnetic waves can be classified according to their wavelength. The following conversions are given: Visible light is limited by wavelengths between 400 and 800 nm. The types of non-visible electromagnetic waves for the human eye are radio waves, microwaves, infrared, ultraviolet, X-rays, and gamma rays. [...]

[...] TEMPERATURE OF STARS - QUALITATIVE ASPECTS The infrared domain is located to the right of the visible spectrum, while the ultraviolet domain is located to the left: The radiation of a hot body is polychromatic because it is associated with several colors (or several wavelengths). As we can see on document the spectral profile of each star is distributed over a wide range of wavelengths, with different light intensities. As the temperature of a body increases, we can see on document 3 that the intensity of the thermal radiation emitted also increases. [...]

[...] According to the different emission spectral profiles of document we can affirm that the temperature of Arcturus is between 4000 and 5000K. THE TEMPERATURE OF STARS - TOWARDS WIEN'S LAW Using the Profil spectral corps noir simulation, we complete the following table. On the last line, we calculate the product of (which is left in nm) by the temperature (in K). Situation 1 Situation 2 Situation 3 Situation 4 Situation 5 Situation 6 Situation 7 We realize that for each wavelength value, the product a almost always the same value. One deduces the Wien's law: . [...]