Stellar atmosphere: Facts, Discussion Forum, and Encyclopedia Article

Stellar atmosphere

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	Topics Stellar atmosphere Topic Home The stellar atmosphere is the outer region of the volume of a starStar A star is a massive, compact body of plasma in outer space that is held together by its own gravity and, unlike a planet, is... , lying above the stellar core, radiation zoneRadiation zone The radiation zone is the middle zone in the sun's interior.... and convection zoneConvection zone The convection zone is the outermost layer of the Sun's interior.... . It is divided into several regions of distinct character: The photospherePhotosphere The photosphere of an astronomical object is the region at which the optical depth becomes one for a photon of wavelength eq... , which is the lowest and coolest part of the star's atmosphere, is the part which we see. LightLight Light is electromagnetic radiation with a wavelength that is visible to the eye or, in a technical or scientific context, e... escaping from the surface of the star stems from this region and passes through the higher layers. The photosphere of the SunFacts About Sun \|+ The Sun \|+\|-\| colspan="2" align="center" \| \|-... has a temperature of about 5780 KKelvin The Kelvin scale is a temperature scale where absolute zero—the coldest possible temperature where there is no heat en... . StarspotStarspot Starspots are equivalent to sunspots but located on other stars.... s, cool regions of disrupted magnetic fieldMagnetic field In physics, a magnetic field is that part of the electromagnetic field that exists when there is a changing electric field.... lie on the photosphere. Above the photosphere lies the chromosphereChromosphere Summary The chromosphere is a thin layer of the Sun's atmosphere just above the photosphere, roughly 10,000 kilometers deep .... . This part of the atmosphere first cools down and then starts to heat up to about 10 times the temperature of the photosphere. Above the chromosphere lies the transition region, where the temperature increases rapidly on a distance of only around 100 km. Beyond this region is the outermost part of the stellar atmosphere, the coronaCorona In astronomy, a corona is the luminous plasma "atmosphere" of the Sun or other celestial body, extending millions of kilomet... , a tenuous but extremely hot (million K) plasmaPlasma (physics) In physics and chemistry, a plasma is typically an ionized gas, and is usually considered to be a distinct phase of ma... . While all stars on the main sequenceMain sequence The main sequence of the Hertzsprung-Russell diagram is the curve along which the majority of stars are located.... feature transition regions and coronae, not all evolved stars do so. It seems that only some giantsGiant star A Giant star is a star that has stopped fusing hydrogen in its core.... , and very few supergiantFacts About Supergiant Supergiants are the most massive stars.... s possess coronae. An unresolved problem in stellar astrophysicsAstrophysics Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of ce... is the question as to how exactly the corona can be heated to such high temperatures. The answer lies in magnetic fieldMagnetic field In physics, a magnetic field is that part of the electromagnetic field that exists when there is a changing electric field.... s, but the exact mechanism remains unclear. During a total solar eclipseSolar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring Earth's view o... , the photosphere of the Sun is obscured, revealing the other layers of the atmosphere. Under these conditions, the chromosphere appears as a rough reddish ring, and the corona appears as a tufted halo.