NASA Researchers Confirm Exoplanet HAT-P-11b Has Water Vapor and Clear Skies
Data from three NASA telescopes have helped researchers take a significant leap towards being able to measure the atmospheric conditions on exoplanets. The Spitzer, Kepler and Hubble telescopes have combined to provide researchers with data that suggests the Exoplanet, HAT-P-11b, has clear skies and water vapor present in its atmosphere.
"This discovery is a significant milepost on the road to eventually analyzing the atmospheric composition of smaller, rocky planets more like Earth," said NASA's John Grunsfeld. "Such achievements are only possible today with the combined capabilities of these unique and powerful observatories."
(An artist's impression of an exoplanet like HAT-P-11 passing in front of its host star - Credit: NASA/JPL-Caltech)
Classed as an exo-Neptune, HAT-P-11b orbits a star located in the Cygnus constellation roughly 120 light years from Earth. Researchers believe the exoplanet has a gaseous atmosphere and a rocky core, but until now no measurements pertaining to the atmospheric composition of such a planet had been possible. In order to gain that data, a team of astronomers used a technique known as transmission spectroscopy, which involves observing a planet as it passes in front of its host star. As starlight hits the edges of the planet's atmosphere it interacts with certain molecules that are present. If water vapor is present the starlight is absorbed, an interaction that leaves a light signature which is detectable by telescope observation.
In the case of HAT-P-11b, Hubble picked up these light signatures and, after cross-checking their findings with data from Spitzer and Kepler, the team of astronomers were able to confirm that water vapor was present in the exoplanet's atmosphere. Along with that discovery came the indication that, because the interaction between water vapor and starlight was visible, the exoplanet's sky contained no clouds that would normally have blocked the telescope's view.
The data will help researchers gain an understanding of how HAT-P-11b was formed and what exactly its chemical make-up consists of. "We think that exo-Neptunes may have diverse compositions, which reflect their formation histories," said study co-author Heather Knutson of Caltech. "Now with data like these, we can begin to piece together a narrative for the origin of these distant worlds. The work we are doing now is important for future studies of super-Earths and even smaller planets, because we want to be able to pick out in advance the planets with clear atmospheres that will let us detect molecules."
For more information on this discovery, read the full NASA release.