We report the discovery of WASP-78b and WASP-79b , two highly-bloated Jupiter-mass exoplanets orbiting F-type host stars .
WASP-78b orbits its V = 12.0 host star ( TYC 5889-271-1 ) every 2.175 days and WASP-79b orbits its V = 10.1 host star ( CD-30 1812 ) every 3.662 days .
Planetary parameters have been determined using a simultaneous fit to WASP and TRAPPIST transit photometry and CORALIE radial-velocity measurements .
For WASP-78b a planetary mass of 0.89 \pm 0.08 M _ { Jup } and a radius of 1.70 \pm 0.11 R _ { Jup } is found .
The planetary equilibrium temperature of T _ { P } = 2350 \pm 80 K for WASP-78b makes it one of the hottest of the currently known exoplanets .
WASP-79b its found to have a planetary mass of 0.90 \pm 0.08 M _ { Jup } , but with a somewhat uncertain radius due to lack of sufficient TRAPPIST photometry .
The planetary radius is at least 1.70 \pm 0.11 R _ { Jup } , but could be as large as 2.09 \pm 0.14 R _ { Jup } , which would make WASP-79b the largest known exoplanet .