We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP-43 b , in addition to eight new measurements of the radial velocity of the star .
Thanks to this extensive data set , we improve significantly the parameters of the system .
Notably , the largely improved precision on the stellar density ( 2.41 \pm 0.08 \rho _ { \odot } ) combined with constraining the age to be younger than a Hubble time allows us to break the degeneracy of the stellar solution mentioned in the discovery paper .
The resulting stellar mass and size are 0.717 \pm 0.025 M _ { \odot } and 0.667 \pm 0.011 R _ { \odot } .
Our deduced physical parameters for the planet are 2.034 \pm 0.052 M _ { Jup } and 1.036 \pm 0.019 R _ { Jup } .
Taking into account its level of irradiation , the high density of the planet favors an old age and a massive core .
Our deduced orbital eccentricity , 0.0035 _ { -0.0025 } ^ { +0.0060 } , is consistent with a fully circularized orbit .
We detect the emission of the planet at 2.09 \mu m at better than 11- \sigma , the deduced occultation depth being 1560 \pm 140 ppm .
Our detection of the occultation at 1.19 \mu m is marginal ( 790 \pm 320 ppm ) and more observations are needed to confirm it .
We place a 3- \sigma upper limit of 850 ppm on the depth of the occultation at \sim 0.9 \mu m. Together , these results strongly favor a poor redistribution of the heat to the night-side of the planet , and marginally favor a model with no day-side temperature inversion .