We present three newly discovered sub-Jupiter mass planets from the SuperWASP survey : WASP-54b is a heavily bloated planet of mass 0.636 ^ { +0.025 } _ { -0.024 } M _ { J } and radius 1.653 ^ { +0.090 } _ { -0.083 } R _ { J } .
It orbits a F9 star , evolving off the main sequence , every 3.69 days .
Our MCMC fit of the system yields a slightly eccentric orbit ( e = 0.067 ^ { +0.033 } _ { -0.025 } ) for WASP-54b .
We investigated further the veracity of our detection of the eccentric orbit for WASP-54b , and we find that it could be real .
However , given the brightness of WASP-54 V=10.42 magnitudes , we encourage observations of a secondary eclipse to draw robust conclusions on both the orbital eccentricity and the thermal structure of the planet .
WASP-56b and WASP-57b have masses of 0.571 ^ { +0.034 } _ { -0.035 } M _ { J } and 0.672 ^ { +0.049 } _ { -0.046 } M _ { J } , respectively ; and radii of 1.092 ^ { +0.035 } _ { -0.033 } R _ { J } for WASP-56b and 0.916 ^ { +0.017 } _ { -0.014 } R _ { J } for WASP-57b .
They orbit main sequence stars of spectral type G6 every 4.67 and 2.84 days , respectively .
WASP-56b and WASP-57b show no radius anomaly and a high density possibly implying a large core of heavy elements ; possibly as high as \sim 50 M _ { \oplus } in the case of WASP-57b .
However , the composition of the deep interior of exoplanets remain still undetermined .
Thus , more exoplanet discoveries such as the ones presented in this paper , are needed to understand and constrain giant planets ’ physical properties .