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Measurements of the sun showed that the radiation sent out from its surface and reaching the ground on Earth is usually consistent with the spectrum of a black body with a temperature in the range of 5,500–6,000 K (5,230–5,730 °C), except that there was no radiation below a wavelength of about 310 nm at the ultraviolet end of the spectrum ...
A K-type star's habitable zone approximately ranges between 0.1–0.4 to 0.3–1.3 AU from the star. Here, exoplanets will receive only a relatively small amount of ultraviolet radiation, especially so towards the outer edge.
Each parameter could have a corresponding zone. Some of the named zones include: [29] [30] Ultraviolet habitable zone: a zone where the ultraviolet (UV) radiation from a star is neither too weak nor too strong for life to exist. [31] Life needs the correct amount of ultraviolet for synthesis of biochemicals.
In the Sun, the region between the solar core at 0.2 of the Sun's radius and the outer convection zone at 0.71 of the Sun's radius is referred to as the radiation zone, although the core is also a radiative region. [1] The convection zone and the radiative zone are divided by the tachocline, another part of the Sun.
The ozone–oxygen cycle is the process by which ozone is continually regenerated in Earth's stratosphere, converting ultraviolet radiation (UV) into heat. In 1930 Sydney Chapman resolved the chemistry involved. The process is commonly called the Chapman cycle by atmospheric scientists.
Free radicals of chlorine (Cl ·), formed by the action of ultraviolet radiation on chlorofluorocarbons (CFCs) and sea salt, are known to catalyze the breakdown of ozone in the atmosphere. There are two other possibilities for decomposing ozone in the gas phase: Thermal decomposition, in which the ozone is decomposed using only the action of heat.
Given the length of the main sequence in G-type stars, [26] the levels of ultraviolet radiation in their habitable zone, [4] the semi-major axis of the inner boundary of this region [19] and the distance to their tidal locking limit, [27] among other factors, yellow dwarfs are considered to be the most hospitable to life next to K-type stars. [1]
The ultraviolet radiation in sunlight has both positive and negative health effects, as it is both a requisite for vitamin D 3 synthesis and a mutagen. Sunlight takes about 8.3 minutes to reach Earth from the surface of the Sun. [ 3 ] A photon starting at the center of the Sun and changing direction every time it encounters a charged particle ...