Short answers, pulled from the story.
A fusor is any celestial object capable of achieving nuclear fusion at some point during its lifetime. This classification includes objects that reach roughly thirteen Jupiter masses to begin fusing deuterium isotopes.
Gibor Basri stood before the International Astronomical Union in 2003 to propose replacing existing terms with the word fusor. He argued this change was necessary to create clarity among scientists studying these bodies.
Objects reaching roughly thirteen Jupiter masses can begin fusing heavy hydrogen isotopes and qualify as fusors. Sustained protium fusion requires around eighty Jupiter masses, which distinguishes true stars from other massive objects.
Active stars fall under the proposed fusor category alongside many brown dwarfs because they achieve deuterium fusion. Any body reaching this threshold qualifies regardless of whether it reaches full stellar status or burns only briefly in youth.
Planemos become round non-fusor objects that lack nuclear reactions entirely while planets form as planemos orbiting a fusor. The distinction relies on whether the primary orbit is now or was in the past around a fusor.