Here's a breakdown:
* Coma: The fuzzy, cloud-like atmosphere that surrounds the nucleus of a comet. It's formed when the nucleus is heated by the Sun, causing ices to sublimate (turn directly from solid to gas). The coma is composed of dust and gas, and it can be very large, sometimes stretching for millions of kilometers.
* Tail: The long, streaming tail of a comet, which is also formed by the interaction of the coma with the solar wind. There are two main types of tails: dust tails and ion tails.
So, while the coma is a halo-like appearance, it's not referred to as a halo. The term "halo" is generally used to describe a ring of light around the Sun or Moon.
