comet tail

A comet's tail is a spectacular feature that forms when the comet approaches the Sun. Composed primarily of volatile ices and dust, the comet's nucleus heats up, causing the ices to sublimate (turn directly into gas). This process creates a bright atmosphere around the nucleus called a coma.1

As the coma's gas and dust are released, they interact with sunlight and the solar wind, forming two distinct tails. One tail, known as the ion or plasma tail (Type I), is made of ionized molecules and radicals. It is pushed directly away from the Sun by the solar wind, appearing long, narrow, and often blue. The other tail, the dust tail (Type II), consists of dust particles pushed away by radiation pressure. This tail is broader, curved, and typically yellowish, following the comet's orbital path. Sometimes, a projection effect can create an "anti-tail" that appears to point toward the Sun.2