Assertion: asteroid belt's object | /r/IsA | comet
Facets:
value: previously
type: TEMPORAL
Source sentences:
text: An object is classified as a comet when it displays “cometary activity”—i.e., a coma or tail (or any evidence of gas or dust coming from it).
text: When the IAU introduced the class small Solar System bodies in 2006 to include most objects previously classified as minor planets and comets, they created the class of dwarf planets for the largest minor planets –