Fanaroff-Riley Class II (FR-II)
radeh-ye Fanarof-Riley II
Fr.: Fanaroff-Riley de type II
In the → Fanaroff-Riley classification, → radio sources with hotspots in their lobes at distances from the center which are such that RFR > 0.5. The → radio jets in FR-II sources are expected to be highly → supersonic, allowing them to travel large distances.