Answer the following question given this paragraph: 

The corona ( Figure below ) is the outermost part of the Sun's atmosphere. It is the Sun’s halo, or “crown. ” With a temperature of 1 to 3 million K, the corona is much hotter than the photosphere. The corona extends millions of kilometers into space. Sometime you should try to see a total solar eclipse. If you do, you will see the Sun’s corona shining out into space.


Q: What is the outermost part of the sun's atmosphere called?


A:
corona