Ruling out the Orbital Decay of the WASP-43b Exoplanet
Résumé
We present 15 new transit observations of the exoplanet WASP-43b in the I‧, g‧, and R filters with the 1.0 m telescopes of Las Cumbres Observatory Global Telescope Network and the IAC80 telescope. We combine our 15 new light curves with 52 others from the literature, to homogeneously analyze all the available transit light curves of this exoplanet. By extending the time span of the monitoring of the transits to more than five years, and by analyzing the individual mid-times of 72 transits, we study the proposed shortening of the orbital period of WASP-43b. We estimate that the times of transit are well-matched by our updated ephemeris equation, using a constant orbital period. We estimate an orbital period change rate no larger than \dot{P} = -0.02 ± 6.6 ms yr-1, which is fully consistent with a constant period. Based on the timing analysis, we discard stellar tidal dissipation factors Q* < 105. In addition, we update the system parameters: a/Rs = 4.867(23), I = 82.11(10)°, and Rp/Rs = 0.15942(41), noticing a difference in the relative size of the planet between optical and NIR bands.