Saturday, February 6, 2016

The Orbit of WASP-43b is Probably Decaying

WASP-43b is a hot-Jupiter with twice the mass of Jupiter, and a radius similar to Jupiter’s. It orbits its host star in an extremely close-in orbit. The orbital period of WASP-43b is only 0.8 days. WASP-43b is one of the most massive planets known to have an extremely short orbital period. Because WASP-43b is so close to its host star, the planet is expected to experience orbital decay due to tidal interactions with its host star.

Jiang et al. (2015) present eight new transit light curves of WASP-43b, and by combining it with previously obtained data, the team found that the orbit of WASP-43b is likely to be decaying. The variations in the transit timings appear to indicate that the orbital period of WASP-43b is decaying at a rate of roughly 3 seconds per hundred years. At this rate, WASP-43b is expected to be tidally disrupted by its host star in just a few million years.

Jiang et al. (2015), “The Possible Orbital Decay and Transit Timing Variations of the Planet WASP-43b”, arXiv:1511.00768 [astro-ph.EP]