Wednesday, September 24, 2014 - 10:00 From NASA Reports

Scientists detected water-vapor molecules in an exoplanet's atmosphere. Artist's concept: NASA.

A gaseous exoplanet the size of Neptune has clear skies and steamy water vapor, according to a new study appearing in the journal Nature. This is the smallest planet from which molecules of any kind have been detected.

     Astronomers used data from three NASA space telescopes -- Hubble, Spitzer and Kepler -- in their research of the Neptune-sized planet.
     "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 the Nature study. "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."
     Clouds can obscure the underlying molecules that reveal information about a planet’s composition and history, according to NASA. Finding clear skies on a Neptune-size planet is a sign that smaller planets might have good visibility.
     The planet designated HAT-P-11b orbits the star HAT-P-11 and is 120 light-years away in the constellation Cygnus. It completes an orbit roughly once every five days. The planet is thought to have a rocky core and gaseous atmosphere.
     A planet's size matters when analyzing atmospheres. Larger Jupiter-like planets are easier to see because of their impressive girth and relatively inflated atmospheres. Researchers already have detected water vapor in the atmospheres of larger planets. The handful of smaller planets observed previously were more difficult to analyze because they appeared to be cloudy.
     A NASA administrator called the study a "significant milepost" on the road to analyzing the atmospheric composition of smaller, rocky Earth-like planets.

ICE COVERAGE CONTINUES DOWNWARD TREND: Arctic sea ice coverage continued its below-average trend this year as the ice declined to its annual minimum on Sept. 17, according to the NASA-supported National Snow and Ice Data Center (NSIDC) at the University of Colorado, Boulder.
     Over the 2014 summer, Arctic sea ice melted back from its maximum extent reached in March to a coverage area of 1.94 million square miles, according to analysis from NASA and NSIDC scientists. This year’s minimum extent is similar to last year’s and below the 1981-2010 average of 2.40 million square miles.
     "Arctic sea ice coverage in 2014 is the sixth lowest recorded since 1978. The summer started off relatively cool and lacked the big storms or persistent winds that can break up ice and increase melting," said Walter Meier, a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
     While summer sea ice has covered more of the Arctic in the last two years than in 2012’s record low summer, this is not an indication that the Arctic is returning to average conditions, Meier said. This year’s minimum extent remains in line with a downward trend; the Arctic Ocean is losing about 13 percent of its sea ice per decade.

NASA In Brief: Scientists to study Arctic Ice Melt