Did 12 astronauts die when the challenger space shuddle exploded in 1986?

Six astronauts and one civilian teacher died in the Challenger explosion. They were:

Francis R. "Dick" Scobee, commander

Michael J. Smith, pilot

Ellison Onizuka, Mission Specialist 1

Judith A. Resnik, Mission Specialist 2

Ronald McNair, Mission Specialist 3

Sharon Christa McAuliffe (civilian) Payload Specialist 1

Gregory Jarvis, Payload Specialist 2