potentially hazardous asteroid (PHA) seyyârak-e tavandâné âpenâk Fr.: astéroïde potentiellement dangereux An asteroid that could make a threatening close approach to the Earth. In technical terms a PHA is defined as having an → absolute magnitude of 22 or brighter and an → Earth Minimum Orbit Intersection Distance (MOID) of less than 0.05 → astronomical unit or 7.5 million km. → potentially; → hazardous; → asteroid. |