The solid portion of a comet—the only portion that exists when the comet is far from the Sun.
Comet is the solar system is an icy small body which passes close to the sun and in this process, it warms and relapses gases called degassing. These comets sometimes show a tail like an appearance.
Learn more about the part of a comet that exists even when it is very far away.
brainly.com/question/7567610.