photosphere

pho·to·sphere  (ft-sfîr)

n.

The visible outer layer of a star, especially of the sun.

---

photo·spheric (-sfîrk, -sfrk) adj.

---

photosphere [ˈfəʊtəʊˌsfɪə]

n

(Astronomy) the visible surface of the sun, several hundred kilometres thick

photospheric  [ˌfəʊtəʊˈsfɛrɪk] adj

---

photosphere  (ft-sfîr)

The lowest visible layer of a star, lying beneath the chromosphere and the corona. Stars are made entirely of gas and thus have no surface per se, but the gas beneath the photosphere is opaque, so the photosphere acts as their effective visible surface; it is also the boundary from which the Sun's diameter is measured. The Sun's photosphere is a very thin layer made up of numerous granules (transient convective cells) where hot gases rise and give off light and heat. The photosphere of the Sun has a temperature of around 6,000°K and is the region in which sunspot activity is located.

Thesaurus

Noun

1.

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"