Аннотация:Based on the shape characteristics of reflectance spectra of some asteroids with H2O ice sublimation activity having elevated reflectance in the UV-VIS-range, we suspected a transient similar activity on (162173) Ryugu, a Cg-type potentially hazardous near-Earth asteroid (NEA) of Apollo’s family, ob-served by F. Vilas in 2007 [3]. Asteroid (162173) Ryugu has been selected as a target of Japan's Hayabusa 2 space mission, which will return a sample of the asteroid in 2020.
We analyze reflectance spectra of Ryugu obtained by different authors and discuss possible mechanisms of ice preservation on this and similar primitive NEAs.