Arp 104

NGC 5216: UGC 8528 • PGC 47598 • MCG 11-17-4 • CGCG CGCG 317-2 316-19 • • J13320682 6242029 2MASX • 3590 GC • H II -841 • h 1635 NGC 5218: UGC 8529 • PGC 47603 • MCG 11-17-5 • CGCG CGCG 317-3 316-20 • • J13321042 6246039 2MASX • 3592 GC • H II -842 • h 1636

Arp 104, Engl. also known as Keenan's system is an interacting pair of galaxies in the constellation Ursa Major. It consists of the two galaxies NGC 5216 and NGC 5218, which are connected by a dim bridge. The system is about 40 Mpc away.

The object was discovered on 19 March 1790 by William Herschel.