Researchers find 'warm Neptune' with water in its atmosphere

Researchers have discovered a planet with an atmosphere that contains clouds foreign to the type we know as well as a 'strong water signature' and high levels of both helium and hydrogen. The planet is called HAT-P-26b, and it circles around a star that is about double the age of our own sun. Researchers with the University of Maryland and NASA describe this exoplanet as a 'warm Neptune' due to its similar size and the nature of its orbit relative to its star.

This warm Neptune, as it is being called, does't shown signs of being a water world, meaning no one should anticipate the presence of big oceans. However, researchers have found evidence of water in the atmosphere, one of the best levels thus far found on an exoplanet of this size. As well, the clouds are described as, for the most part, being foreign to the kind we're used to on Earth.

Researchers anticipate these clouds being composed of disodium sulfide rather than the water vapor, and as such they're likely grayish in color. The atmosphere has been described as ancient, helping shed light on the nature of planets this size and how they may form. Though it is compared with Neptune, this exoplanet was likely to have formed near its star or, possibly, later on in its system's overall development.

Another deviation from the big planets like Neptune is HAT-P-26b's metallicity — that is, how densely present heavy elements are on the planet. While big planets like Neptune have metallicities about one hundred times that of the sun, this exoplanet only has a metallicity of about 4.8 times that of its own star. This is about the equivalent of our system's Jupiter, which runs between a 2 and 5 on the metallicity scale.

SOURCE: EurekAlert