NationMaster - Encyclopedia: Stellar atmosphere

The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. It is divided into several regions of distinct character: Image File history File linksMetadata Download high-resolution version (3543x3489, 2027 KB) Summary Description: Solar eclipse 1999 in France view 4 Additional noise reduction performed by Diliff. ... Image File history File linksMetadata Download high-resolution version (3543x3489, 2027 KB) Summary Description: Solar eclipse 1999 in France view 4 Additional noise reduction performed by Diliff. ... 1999 (MCMXCIX) was a common year starting on Friday, and was designated the International Year of Older Persons by the United Nations. ... This article is about the astronomical object. ... The radiation zone is the middle zone in the suns interior. ... The convection zone is the outermost layer of the suns interior. ...

The photosphere, which is the lowest and coolest part of the star's atmosphere is the part which we see. Light escaping from the surface of the star stems from this region and passes through the higher layers. The photosphere of the Sun has a temperature (effective temperature) of about 5780 K. Starspots, cool regions of disrupted magnetic field lie on the photosphere. The photosphere of an astronomical object is the region at which the optical depth becomes one for a photon of wavelength equal to 5000 angstroms. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength[1]. The elementary particle that defines light is the photon. ... The Sun is the star at the center of the Solar System. ... The effective temperature of a star is the temperature of a black body with the same luminosity (L) as the star and is defined according to the Stefan-Boltzman law L = sigma T_{eff}^{4}. The effective temperature of our Sun is around 5,800 kelvins (K) and correspond to... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zeroâ€”the lowest possible temperature where nothing could be colder and no heat energy remains in a substanceâ€”is defined as zero kelvin (0 K). ... 400 year sunspot history A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings, and intense magnetic activity. ... Current (I) flowing through a wire produces a magnetic field () around the wire. ...

Above the photosphere lies the chromosphere. This part of the atmosphere first cools down and then starts to heat up to about 10 times the temperature of the photosphere. The chromosphere (literally, color sphere) is a thin layer of the Suns atmosphere just above the photosphere, roughly 10,000 kilometers deep. ...

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 corona, a tenuous but extremely hot (million K) plasma. While all stars on the main sequence feature transition regions and coronae, not all evolved stars do so. It seems that only some giants, and very few supergiants possess coronae. An unresolved problem in stellar astrophysics is the question as to how exactly the corona can be heated to such high temperatures. The answer lies in magnetic fields, but the exact mechanism remains unclear. TRACE 19. ... In astronomy, a corona is the luminous plasma atmosphere of the Sun or other celestial body, extending millions of kilometres into space, most easily seen during a total solar eclipse, but also observable in a coronagraph. ... A plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... Giant star is a star that has stopped fusing hydrogen in its core. ... Supergiants are the most massive stars. ... Spiral Galaxy ESO 269-57 Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature, and chemical composition) of celestial objects such as stars, galaxies, and the interstellar medium, as well as their interactions. ... Current (I) flowing through a wire produces a magnetic field () around the wire. ...

During a total solar eclipse, 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. Photo taken during the 1999 eclipse. ...

Category: Star stubs The Sun is the star at the center of the Solar System. ... Image File history File links Sun_picture. ... The structure of the Sun The core of the Sun is considered to extend from the center to about 0. ... The radiation zone is the middle zone in the suns interior. ... The convection zone is the outermost layer of the suns interior. ... The photosphere of an astronomical object is the region at which the optical depth becomes one for a photon of wavelength equal to 5000 angstroms. ... The chromosphere (literally, color sphere) is a thin layer of the Suns atmosphere just above the photosphere, roughly 10,000 kilometers deep. ... TRACE 19. ... In astronomy, a corona is the luminous plasma atmosphere of the Sun or other celestial body, extending millions of kilometres into space, most easily seen during a total solar eclipse, but also observable in a coronagraph. ... The locations of Voyagers 1 and 2 as of 2005 In space physics, the termination shock is the boundary marking one of the outer limits of the suns influence. ... The heliosphere is a bubble in space produced by the solar wind. ... The heliopause is the boundary between the heliosphere and the interstellar medium outside the solar system. ... The locations of Voyagers 1 and 2 as of 2005 The heliosheath is the zone between the termination shock and the heliopause at the outer border of the solar system. ... In a planetary magnetosphere, the bow shock is the boundary at which the solar wind abruptly drops as a result of its approach to the magnetopause. ... A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings and intense magnetic activity, which inhibits convection, forming areas of low surface temperature. ... A facula (plural: faculae) is literally a bright spot. ... Solar photosphere Granules on the photosphere of the Sun are caused by convection currents of plasma within the Suns convective zone. ... Supergranulation is one of the influences on the Sun. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... Discovered in 1877 by Father Angelo Secchi of the Vatican Observatory in Rome, a spicule is a dynamic jet of about 500km diameter on the Sun. ... Typical coronal loops observed by TRACE Coronal loops form the basic structure of the lower corona and transition region of the Sun. ... A Solar Flare and CME, courtesy NASA A solar flare is a violent explosion in the Suns atmosphere with an energy equivalent to a billion megatons, traveling normally at about 1 million km per hour (about 0. ... Filaments surrounding a solar flare, caused by the interaction of the plasma in the Suns atmosphere with its magnetic field. ... A composite image showing two CMEs (at 2 oclock and 8 oclock), with the sun at center. ... Animation of a Moreton wave which occurred on December 6, 2006 A Moreton wave is a kind of shockwave on the Suns chromosphere. ... Coronal holes are areas where the Suns corona is darker, colder, and has lower-density plasma than average. ... Major features of the Solar System (not to scale, from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth & Moon, and Mars. ... 400 year history of sunspot numbers. ... The solar dynamo is the physical process that generates the Suns magnetic field. ... Heliospheric current sheet The Heliospheric current sheet (HCS) is the surface within the Solar System where the polarity of the Suns magnetic field changes from north to south. ... Solar irradiance spectrum at top of atmosphere. ... Photo taken during the 1999 eclipse. ...