Mystery of missing exoplanet water solved

The missing water mystery has been solved in a comprehensive survey of exoplanets.

The survey of 10 hot, Jupiter-sized exoplanets conducted with NASA's Hubble and Spitzer space telescopes has led a team to solve a long-standing mystery as to why some of these worlds seem to have less water than expected.

The findings offer new insights into the wide range of planetary atmospheres in our galaxy and how planets are assembled.

Of the nearly 2,000 planets confirmed to be orbiting other stars, a subset are gaseous planets with characteristics similar to those of Jupiter but orbit very close to their stars, making them blistering hot.

Their close proximity to the star makes them difficult to observe in the glare of starlight. Due to this difficulty, Hubble has only explored a handful of hot Jupiters in the past. These initial studies have found several planets to hold less water than predicted by atmospheric models.

Lead author David Sing from the University of Exeter said that they found the planetary atmospheres to be much more diverse than they expected.

The results suggest it's simply clouds hiding the water from prying eyes, and therefore rule out dry hot Jupiters, explained co-author Jonathan Fortney from the University of California. "The alternative theory to this is that planets form in an environment deprived of water, but this would require us to completely rethink our current theories of how planets are born."

The results are published in the British science journal Nature.