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How does a dust tail form on a comet?

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Comet Comet McNaught with filamentary tail and the Moon over the Pacific Ocean, photographed from Paranal Observatory, Chile, January 2007.

A comet's dust tail, also known as a Type II tail, forms through the interaction between solar radiation and the fine dust particles released from the comet's nucleus.1

As a comet approaches the Sun, its volatile ices sublimate, creating an outflowing atmosphere called a coma that carries away fine dust grains. While gas molecules are ionized and swept away by the solar wind, the fine dust particles are pushed away from the Sun by radiation pressure.231

This process results in a broad, curved, and often yellowish tail that follows the comet along its orbit. Because these dust grains are pushed into larger orbits than the comet nucleus, they move more slowly according to the laws of planetary motion, causing the tail to lag behind the nucleus as it travels. Eventually, this material disperses into the zodiacal dust cloud.1