Due to tidal deceleration, it is expected to spiral toward and eventually merge with its host star, WASP-18, in less than a million years.

A team led by Coel Hellier, a professor of astrophysics at Keele University in England, discovered the exoplanet in 2009.

[1] Scientists at Keele and at the University of Maryland are working to understand whether the discovery of this planet so shortly before its expected demise (with less than 0.1% of its lifetime remaining) was fortuitous, or whether tidal dissipation by WASP-18 is actually much less efficient than astrophysicists typically assume.

Phobos orbits Mars at a distance of only about 9,000 km (5,600 mi), 40 times closer than the Moon is to the Earth[7] and is expected to be destroyed in about eleven million years.

[4] A study in 2012, utilizing the Rossiter–McLaughlin effect, determined that the planetary orbit is well aligned with the equatorial plane of the star, with a misalignment equal to 13±7°.