Search results
Results from the WOW.Com Content Network
At the center of the Sun, fusion power is estimated by models to be about 276.5 watts/m 3. [7] Despite its intense temperature, the peak power generating density of the core overall is similar to an active compost heap, and is lower than the power density produced by the metabolism of an adult human. The Sun is much hotter than a compost heap ...
The coolest layer of the Sun is a temperature minimum region extending to about 500 km above the photosphere, and has a temperature of about 4,100 K. [77] This part of the Sun is cool enough to allow for the existence of simple molecules such as carbon monoxide and water. [ 81 ]
The Sun has a core temperature of around 15.7 × 10 6 K, and only 1.7% of 4 He nuclei produced in the Sun are born in the CNO cycle. The CNO-I process was independently proposed by Carl von Weizsäcker [5] [6] and Hans Bethe [7] [8] in the late 1930s.
The Sun's core temperature, at which PP is more efficient In astrophysics , stellar nucleosynthesis is the creation of chemical elements by nuclear fusion reactions within stars . Stellar nucleosynthesis has occurred since the original creation of hydrogen , helium and lithium during the Big Bang .
The temperature of the core region for a VLMS decreases with decreasing mass, while the density increases. For a star with 0.1 M ☉, the core temperature is about 5 MK while the density is around 500 g cm −3. Even at the low end of the temperature range, the hydrogen and helium in the core region is fully ionized. [4]
The Sun is a main-sequence star, and, as such, generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses 620 million metric tons of hydrogen and makes 616 million metric tons of helium each second. The fusion of lighter elements in stars releases energy and the mass that always accompanies it.
Helium is the least water-soluble monatomic gas, [96] and one of the least water-soluble of any gas (CF 4, SF 6, and C 4 F 8 have lower mole fraction solubilities: 0.3802, 0.4394, and 0.2372 x 2 /10 −5, respectively, versus helium's 0.70797 x 2 /10 −5), [97] and helium's index of refraction is closer to unity than that of any other gas. [98]
The surface abundance of Li on the Sun is 140 times less than the protosolar value (i.e. the primordial abundance at the Sun's birth), [18] yet the temperature at the base of the surface convective zone is not hot enough to burn – and hence deplete – Li. [19] This is known as the solar lithium problem.