Acelestial object takes six to seven years to revolve once around the sun. it’s made mostly of ice, some of which vaporizes when it passes near the sun. what is this object?

The object is a comet.

Explanation:

A comet primarily comprises rock, ice, dust, and frozen gases like carbon dioxide, carbon monoxide, ammonia, and methane. It is on certain occasions known as the dirty snowballs, and the present studies done on comets have demonstrated that the ice of comet is enveloped by a crust.  

Comets also comprise various kinds of organic compounds as well as the gases. Comets, when it comes close to the Sun while revolving around it, loses some of the ice from its crust as it gets vaporized due to heat coming from the Sun.  

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