News Release Archive:

News Release 28 of 1057

June 8, 2016 12:30 PM (EDT)

News Release Number: STScI-2016-20

Cloudy Days on Exoplanets May Hide Atmospheric Water

A News Nugget Release

June 8, 2016: Water is a hot topic in the study of exoplanets, including "hot Jupiters," whose masses are similar to that of Jupiter, but lie much closer to their parent star than Jupiter is to the sun. They are estimated to be a scorching 2,000 degrees Fahrenheit, meaning any water they host would take the form of water vapor.

Astronomers have found many hot Jupiters with water in their atmospheres, but other hot Jupiters appear to have none. In a new study, scientists used exoplanet data from a single instrument on NASA's Hubble Space Telescope to uniformly characterize a group of 19 hot Jupiters previously studied with Hubble. They found that as much as half of the water in the atmospheres of the exoplanets may be blocked by these clouds or hazes. The new findings suggest that clouds or haze layers could be preventing a substantial amount of atmospheric water from being detected by space telescopes. The study is the first to quantify how much of the atmosphere would be shielded as a result of clouds or haze.

For illustrations and additional information about this study and Hubble, visit

Illustration Credit: NASA and JPL-Caltech

Science Credit: NASA, ESA, and A. Iyer (JPL)