photosphere - the intensely luminous surface of a star (especially the sun)
surface - the extended two-dimensional outer boundary of a three-dimensional object; "they skimmed over the surface of the water"; "a brush small enough to clean every dental surface"; "the sun has no distinct surface"
Sun - the star that is the source of light and heat for the planets in the solar system; "the sun contains 99.85% of the mass in the solar system"; "the Earth revolves around the Sun"
Just as Earth's atmosphere contains layers such as the troposphere and stratosphere, the solar atmosphere is made up of four distinct layers: the
photosphere, chromosphere, transition region, and corona.
The first or final piece of solar
photosphere shining through the deepest valley on the Moon's edge creates, with the ring band of the inner corona, the most spectacular of all eclipse phenomena: the diamond ring.