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Solar prominence
From Wikipedia, the free encyclopedia
A solar prominence is a large bright feature extending outwards from the sun's surface, often in a loop configuration. Prominences are anchored to the solar surface in the photosphere, and extend outwards into the solar corona. While the corona consists of extremely hot ionized gases, known as plasma, which do not emit much visible light, prominences contain much cooler plasma, similar in composition to that of the chromosphere. A prominence forms over timescales of about a day, and stable prominences may persist in the corona for several months. Some prominences break apart and give rise to coronal mass ejections.
Despite decades of study, the mechanism by which prominences form is not yet well understood. Theories have not satisfactorily explained how prominences can remain stable for such a long time when they are much denser than their surroundings. Magnetic fields are known to be the dominant influence on gas motions within the corona, but the exact form of magnetic interaction required to produce and maintain a large prominence has yet to be determined.
A typical prominence extends over many thousands of kilometres; the largest observed by SOHO was seen in 1997 and was some 350,000 km (216,000 miles) long [1] - some 28 times the diameter of the Earth. The mass contained within a prominence is typically of the order of 100 billion tonnes of material.
If a solar prominence occurs on the disc of the sun it appears darker than its background (due to the lower temperature of the plasma). These are referred to as solar filaments.
- ^ EIT gallery. Retrieved on 2005-10-15.
- Galsgaard, K.; Longbottom, A.W. (1999). "Formation of solar prominences by flux convergence". Astrophysical Journal 510: 444.
- Low, B.C.; Fong, B.; Fan, Y. (2003). "The mass of a solar quiescent prominence". Astrophysical Journal 594: 1060.
- Golub, L.; Pasachoff J.M. (1997). The Solar Corona. Cambridge University Press.
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| Structure | Solar core - Radiation zone - Convection zone |  |
| Atmosphere | Photosphere - Chromosphere - Transition region - Corona | |
| Extended structure | Termination Shock - Heliosphere - Heliopause - Heliosheath - Bow Shock | |
| Solar phenomena | Sunspots - Faculae - Granules - Supergranulation - Solar Wind - Spicules - Coronal loops - Solar Flares - Solar Prominences - Coronal Mass Ejections - Moreton Waves - Coronal Holes | |
| Other | Solar System - Solar Variation - Solar Dynamo - Heliospheric Current Sheet - Solar Radiation - Solar Eclipse - Spectral Class: G2 | |
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