The killing of Al-Qaeda's Zawahiri: What is Hellfire R9X missile?

On August 1st, the US President announced that the US had killed the Al-Qaeda leader Ayman al-Zawahiri. Without any sign of an explosion, the US government took out Al-Qaeda leader Ayman al-Zawahiri. US officials said that Zawahiri had been in hiding for years and the operation to locate and kill him was the result of "careful patient and persistent" work by the counter-terrorism and intelligence community.