An article appearing in the scientific journal Nature this week highlights that a cloud-free atmosphere has made it possible to see signs of water vapor on a far-distant exo-planet the size of Neptune. Of note, this is the first time scientists have been able to determine the chemical composition of an “exoplanet” that small. To date, only large, Jupiter-like giants were observed with these methods.
The complex project involved three space telescopes, and astronomers detected water vapor in the atmosphere of the planet by measuring the colors of light it absorbed when it passed in front of its star. Designated HAT P-11b, the planetary system is found in the constellation Cygnus 124 light-years from Earth. The exoplanet is nearly four times the diameter of earth.
The research was led by a team from the University of Maryland. The astronomers examined the planet’s atmosphere using NASA’s ‘s Hubble, Spitzer and Kepler telescopes.
Expert analysis of exoplanet
Dr Eliza Kempton, a planetary specialist from Grinnell College, said the research of the Maryland group represented another important step in the study of exoplanets.
“Astronomers have detected water vapor in the atmospheres of larger planets – planets that are closer in size to Jupiter. But you can imagine that eventually we want to be able to detect molecules in the atmospheres of even smaller planets. We’d like to be able to look at an Earth-sized planet and measure its gaseous composition. So this is a step on the ladder; we’re stepping down the ladder towards smaller and smaller planets,” Kempton explained in an interview in this week’s Science In Action program on BBC.
Water is the key to life
Most people already understand that the presence of water on exoplanets has obvious implications for life, but in this case, it’s thought that HAT P-11b is too close to its star, and therefore too hot to be habitable.
However, the presence of water will be an important consideration in the future as scientists continue to search for life-bearing planets elsewhere in our galaxy.