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The Chromosphere

THE SUN 

Why We Study the Sun 
The Big Questions 
Magnetism - The Key 

SOLAR STRUCTURE 

The Interior 
The Photosphere 
The Chromosphere 
The Transition Region 
The Corona 
The Solar Wind 
The Heliosphere 

SOLAR FEATURES 

Photospheric Features 
Chromospheric Features 
Coronal Features 
Solar Wind Features 

THE SUN IN ACTION 

The Sunspot Cycle 
Solar Flares 
Post Flare Loops 
Coronal Mass Ejections 
Surface and Interior Flows 
Waves and Helioseismology 

RESEARCH AREAS 

Flare Mechanisms 
3D Magnetic Fields 
The Solar Dynamo 
Sunspot Cycle Predictions 
Solar Wind Dynamics 

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The chromosphere is an irregular layer above the photosphere where the temperature rises from 6000° C to about 20,000° C. At these higher temperatures hydrogen emits light that gives off a reddish color (H-alpha emission). This colorful emission can be seen in prominences that project above the limb of the sun during total solar eclipses. This is what gives the chromosphere its name (color-sphere).

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When the Sun is viewed through a spectrograph or a filter that isolates the H-alpha emission, a wealth of new features can be seen. These features include the chromospheric network of magnetic field elements, bright plage around sunspots, dark filaments across the disk and prominences above the limb.

The chromosphere is the site of activity as well. Changes in solar flares, prominence and filament eruptions, and the flow of material in post-flare loops can all be observed over the course of just a few minutes.

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The chromosphere is also visible in the light emitted by ionized calcium, Ca II, in the violet part of the solar spectrum at a wavelength of 393.4 nanometers (the Calcium K-line). This emission is seen in other solar-type stars where it provides important information about the chromospheres and activity cycles in those stars.

 

 

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Latest Images - BBSO Latest images of the chromosphere in H-alpha and CaK-Line

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Author: David H. Hathaway, david.hathaway@msfc.nasa.gov, (256) 961-7610
Mail Code SD50, NASA/Marshall Space Flight Center, Huntsville, AL 35812

 

Responsible Official: John M. Davis, john.m.davis@msfc.nasa.gov, (256) 961-7600
Mail Code SD50, NASA/Marshall Space Flight Center, Huntsville, AL 35812

 

Last revised 2000 November 09 - D. H. Hathaway


Reproduced from http://science.nasa.gov