Solar core

Solar core
Cross-section of a solar-type star (NASA)

The core of the Sun is considered to extend from the center to about 0.2 to 0.25 of the solar radius.[32] It has a density of up to 150 g/cm3[33][34] (about 150 times the density of water) and a temperature of close to 13,600,000 K (by contrast, the Sun's surface is around 5,800 K). Recent analysis of SOHO mission data favors a faster rotation rate in the core than in the rest of the radiative zone.[32] Through most of the Sun's life, energy is produced by nuclear fusion through a series of steps called the p–p (proton–proton) chain; this process converts hydrogen into helium.[35] Less than 2% of the helium generated in the Sun comes from the CNO cycle.

The core is the only location in the Sun that produces an appreciable amount of heat through fusion; inside 24% of the Sun's radius, 99% of the power has been generated, and by 30% of the radius, fusion has stopped nearly entirely. The rest of the star is heated by energy that is transferred outward from the core and the layers just outside. The energy produced by fusion in the core must then travel through many successive layers to the solar photosphere before it escapes into space as sunlight or kinetic energy of particles.[36][37]

The proton–proton chain occurs around 9.2 × 1037 times each second in the core of the Sun. Since this reaction uses four free protons (hydrogen nuclei), it converts about 3.7 × 1038 protons to alpha particles (helium nuclei) every second (out of a total of ~8.9 × 1056 free protons in the Sun), or about 6.2 × 1011 kg per second.[37] Since fusing hydrogen into helium releases around 0.7% of the fused mass as energy,[38] the Sun releases energy at the mass-energy conversion rate of 4.26 million metric tons per second, 384.6 yottawatts (3.846×1026 W),[1] or 9.192 × 1010 megatons of TNT per second. This mass is not destroyed to create the energy, rather, the mass is carried away in the radiated energy, as described by the concept of mass-energy equivalence.

The energy production per unit time (power) produced by fusion in the core varies with distance from the solar center. At the center of the Sun, fusion power is estimated by model to be about 276.5 watts/m3,[39] a power production density which more nearly approximates reptile metabolism than a thermonuclear bomb.[40] Peak power production in the Sun has been compared to the volumetric heats generated in an active compost heap. The tremendous power output of the Sun is not due to its high power per volume, but instead due to its large size.





Handmade Jewelry
lanzarote holidays