What process initiates the creation of a comet's visible coma when it approaches the Sun?
Answer
Sublimation
As solar radiation warms the nucleus, the ices begin to sublimate, turning directly from solid ice into gas and releasing jets of gas and dust that form the coma.

Related Questions
What evocative term is often used to describe comets, which are built from ice, dust, and frozen gases?What part of a comet serves as the storage unit for frozen materials like rock, dust, and various ices?What process initiates the creation of a comet's visible coma when it approaches the Sun?Which characteristic describes the fainter, straighter tail of a comet?What is the primary compositional difference that leads to the classification of Uranus and Neptune as 'Ice Giants'?What compound gives Uranus and Neptune their characteristic blue-green hues?What evidence suggests that comets played a role in supplying water to Earth?How is the water ice in the mantle of Neptune vastly different from water ice in a comet's nucleus?Where do comets primarily reside when they are considered inert and dark, far from the Sun's influence?What does the existence of the Ice Giants confirm about the early solar nebula?