transition region

American  

noun

Astronomy.

1. a thin and very irregular layer of the sun's atmosphere that separates the hot corona from the much cooler chromosphere.

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transition region Scientific  

1. The area in a seed-bearing plant where the vascular tissue of the root changes into the vascular tissue of the stem. In eudicotyledons, the roots have a solid cylinder of vascular tissue surrounded by cortex. The vascular tissues gradually branch apart and reorient themselves in the stem around a central pith.

2. The thin layer of the solar atmosphere that separates the chromosphere from the corona. In the transition region, temperatures increase from a relatively cool 20,000°K in the chromosphere to the 1,000,000°K and higher temperatures of the corona. Transition region chemistry involves the ionization of hydrogen and other elements; the light produced by this region comes from ionized forms of carbon, oxygen, and silicon.

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Example Sentences

Note the very rapid increase in temperature over a very short distance in the transition region between the chromosphere and the corona.

From Textbooks • Oct. 13, 2016

Appropriately, the part of the Sun where the rapid temperature rise occurs is called the transition region.

From Textbooks • Oct. 13, 2016

However, we now know that while this idea of layers—photosphere, chromosphere, transition region, corona—describes the big picture fairly well, the Sun’s atmosphere is really more complicated, with hot and cool regions intermixed.

From Textbooks • Oct. 13, 2016

In the transition region, the flow can oscillate chaotically between laminar and turbulent flow.

From Textbooks • Aug. 12, 2015