SOLAR SYSTEM

Detailed explanation-1: -The outer layers are the Photosphere, the Chromosphere, the Transition Region and the Corona. IRIS will focus its investigation on the Chromosphere and Transition Region.

Detailed explanation-2: -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.

Detailed explanation-3: -the corona-the outermost, hot shell of the atmosphere. the chromosphere-a transparent layer between the corona and the photosphere. the photosphere-the visible “surface” of the Sun.