Over 100 exoplanets with potentially habitable moons identified

Los Angeles

Scientists have identified more than 100 giant planets existing outside our solar system that may potentially host moons capable of supporting life.

 The finding, published in The Astrophysical Journal, will guide the design of future telescopes for detecting these potential moons and look for tell-tale signs of life, called biosignatures, in their atmospheres.

"There are a total of 175 known moons orbiting the eight planets in our solar system," said Stephen Kane, an associate professor at University of California, Riverside, US.

"While most of these moons orbit Saturn and Jupiter, which are outside the Sun's habitable zone, that may not be the case for the other solar systems," said Kane.

The researchers, including those from the University of Southern Queensland in Australia, identified 121 giant planets that have orbits within the habitable zones of their stars.

 At more than three times the radii of the Earth, these gaseous planets are less common than terrestrial planets, but each is expected to host several large moons.

"Including rocky exomoons in our search for life in space will greatly expand the places we can look," he said.

Following the 2009 launch of NASA's Kepler telescope, thousands of planets existing outside our solar system – called exoplanets – have been identified by scientists.

The primary goal of the Kepler mission is to identify planets that exist within the habitable zones of their stars, meaning that they are neither too hot nor too cold for liquid water - and potentially life - to exist.

Terrestrial (rocky) planets are prime targets in the quest to find life because some of them might be geologically and atmospherically similar to Earth.

Another place to look is around the many gas giants identified during the Kepler mission.

While not the candidates for life themselves, Jupiter-like planets in the habitable zone may harbor rocky moons, called exomoons, which could sustain life.

Scientists have speculated that these exomoons might provide a favorable environment for life, perhaps even better than the Earth, for the reason that they receive energy not only from their stars, but also from radiations reflected off from their planets. However, no exomoons have been confirmed till now.

"Now that we have created a database of the known giant planets in the habitable zone of their star, observations of the best candidates for hosting potential exomoons will be made to help refine the expected exomoon properties," said Michelle Hill, an undergraduate student at the University of Southern Queensland.

"Our follow-up studies will help inform future telescope design so that we can detect these moons, study their properties, and look for signs of life," said Hill. PTI