11509 Thersilochos was discovered by E. W. Elst on 15 November 1990 and it is named after Thersilochus
11509 Thersilochos E. W. Elst 15 November 1990 Thersilochus
(Greek mythology) 
It was discovered on 15 November 1990, by Belgian astronomer Eric Elst at the La Silla Observatory in northern Chile. It was named after the Trojan warrior Thersilochus from Greek mythology. 
