It was discovered via the transit method, and then follow up measurements using the radial velocity method confirmed that WASP-2b was a planet. The planet's mass and radius indicate that it is a gas giant with a similar bulk composition to Jupiter.
The discovery of WASP-2b was made using the transit method, which was followed by radial velocity measurements to confirm its status as a planet. The planet's mass and radius suggest it is a gas giant with a composition similar to Jupiter.