Description: A comet nucleus is the core of a comet. This is a solid object, similar to a dirty snowball, made with ice and rocky, dusty particles. Far from the Sun the nucleus is the sole component of the comet. Closer to the Sun a comet's nucleus is heated due to sunlight. This causes the surface ice to sublimate. The sublimated ice and the dust embedded in it are ejected and surround the nucleus as a coma with a tail pointing away from the Sun.

Related Terms:

• Cometary Coma
• Comet
• Cometary Tail

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

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