Osiris
"HD 209458 b represents a number of milestones in extraplanetary research. It was the first transiting extrasolar planet discovered, the first extrasolar planet known to have an atmosphere, the first extrasolar planet observed to have an evaporating hydrogen atmosphere, the first extrasolar planet found to have an atmosphere containing oxygen and carbon, and one of the first two extrasolar planets to be directly observed spectroscopically. ...
"HD 209458 b has been informally referred to as Osiris, though this name was not given by the astronomers credited with its discovery. The use of the Osiris nickname has faded among astronomers and the media."
"HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earth's solar system."