NASA Telescopes Detecting Clear Skies and Steamy Water Vapor on Neptune-size Exoplanet

A Neptune-size planet with a clear atmosphere is shown crossing in front of its star in this artist's depiction. Such crossings, or transits, are observed by telescopes like NASA's Hubble and Spitzer to glean information about planets' atmospheres.
A Neptune-size planet with a clear atmosphere is shown crossing in front of its star in this artist’s depiction. Such crossings, or transits, are observed by telescopes like NASA’s Hubble and Spitzer to glean information about planets’ atmospheres Image Credit NASA

Is a sign smaller exoplanets could have similar or more hospitable environments

Space news (November 07, 2014) 120 light-years away in the constellation Cygnus –

NASA space scientists using the Hubble, Spitzer and Kepler space telescopes detected clear skies and steamy water vapor on exoplanet HAT-P-11b. This is the first detection of molecules on an exoplanet the size of Neptune or smaller. It’s also a sign smaller exoplanets have similar or more hospitable environments.  

Scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA's Hubble, Spitzer and Kepler space telescopes. Image Credit: NASA/JPL-Caltech
Space scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA’s Hubble, Spitzer, and Kepler space telescopes.
Image Credit: NASA/JPL-Caltech

How did space scientists detect clear skies and steamy vapor on a planet 120 light-years away in the Constellation Cygnus? Astronomers used the Hubble, Spitzer and Kepler space telescopes to observe HAT-P-11b as it passed in front of its parent star in relation to Earth. By analyzing the starlight passing through the atmosphere of the exoplanet, space scientists determined the specific molecules making it up. 

This scientific technique is called Transmission Spectroscopy and it was particularly effective in the case of HAT-P-11b because of this Neptune-size exoplanet (exo-Neptune), unlike previous ones detected, has no clouds in the atmosphere to block the starlight from coming through, which allowed for the detection of water vapor molecules.  

A plot of the transmission spectrum for exoplanet HAT-P-11b, with data from NASA's Kepler, Hubble and Spitzer observatories combined. The results show a robust detection of water absorption in the Hubble data. Transmission spectra of selected atmospheric models are plotted for comparison. Image Credit: NASA/ESA/STScI
A plot of the transmission spectrum for exoplanet HAT-P-11b, with data from NASA’s Kepler, Hubble and Spitzer space observatories combined. The results show a robust detection of water absorption in the Hubble data. Transmission spectra of selected atmospheric models are plotted for comparison.
Image Credit: NASA/ESA/STScI

“This discovery is a significant milepost on the road to eventually analyzing the atmospheric composition of smaller, rocky planets more like Earth,” said John Grunsfeld, assistant administrator for NASA’s Science Mission Directorate in Washington. “Such achievements are only possible today with the combined capabilities of these unique and powerful observatories.” 

“When astronomers go observing at night with telescopes, they say ‘clear skies’ to mean good luck,” said Jonathan Fraine of the University of Maryland, College Park, lead author of a new study appearing in Nature. “In this case, we found clear skies on a distant planet. That’s lucky for us because it means clouds didn’t block our view of water molecules.” 

“We think that exo-Neptunes may have diverse compositions, which reflect their formation histories,” said study co-author Heather Knutson of the California Institute of Technology in Pasadena. “Now with data like these, we can begin to piece together a narrative for the origin of these distant worlds.” 

“We are working our way down the line, from hot Jupiters to exo-Neptunes,” said Drake Deming, a co-author of the study also from the University of Maryland. “We want to expand our knowledge to a diverse range of exoplanets.” 

NASA space scientists will now use the Hubble, Spitzer and Kepler space telescopes to begin looking at more exoplanets the size of HAT-P-11b for clear skies and water vapor. They’ll also hope to use Transmission Spectroscopy to detect smaller exoplanets, more like our home planet, called super-Earths orbiting distant stars. Once the James Webb Space Telescope comes online in 2018, they’ll begin looking at any super-Earths detected for signs of water vapor and other molecules. 

Find more on the Hubble Space Telescope here

More information on the Spitzer Space Telescope can be found here

Look here for more on the Kepler Space Telescope. 

Go here for more information on NASA and the exoplanets discovered.

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