Astrophysics (Index)About

transition region

(solar transition region)
(middle layer of the Sun's atmosphere)

The transition region (or solar transition region) is a relatively thin (on the order of 100 km) layer of the Sun's atmosphere constituting the transition from the chromosphere to the corona above. Outward through the chromosphere, the temperature rises and the transition region is at the point at which the temperature-driven ionization reaches a threshold resulting in much more opacity and absorption, thus increasing temperature outward at a much faster rate. This temperature rise through the region is from on the order of 20,000 K to on the order of 1,000,000 K. Black-body radiation from this layer is in the ultraviolet.

It is presumed stars have a transition region, but the Sun's is the only one subject to much study and observation.

(Sun,stellar atmosphere,corona)
Further reading:

Referenced by pages:
stellar atmosphere