Program: GN-2024A-DD-108

Near-Earth object 1998 KY26 (hereafter KY26) is a rendezvous target of the Hayabusa2 spacecraft mission. KY26 is a ``dark comet'' with cometary non-gravitational accelerations but no visible coma or dust tail appearance. While observations of the non-gravitational accelerations suggest that comet-like activity is present in the object, the exact mechanism and amount of its mass loss are unknown. We propose spectroscopic and deep imaging observations of KY26 during its close approach with the Earth in 2024 June to constrain its taxonomic type and mass loss, providing two independent tests of its mass-loss mechanism. Additionally, our observations will provide the physical information on KY26 that will be useful for planning the Hayabusa2 rendezvous with the asteroid. These observations must be executed within the first half of June since the asteroid will go into solar conjunction and be unobservable from the ground until after the Hayabusa2 spacecraft rendezvous in 2031. We request a total of 2.37 h for our spectroscopic and imaging observations of KY26.