Astronomers should start hunting for planets like the Tatooine in the science fiction series Star Wars, as earth-like worlds could exist in the habitable zones around binary systems, scientists say.
In the Star Wars universe, Tatooine was a circumbinary planet that had two suns. In September last year, Nasa’s Kepler space telescope had discovered the first real-life circumbinary planet, Kepler-16b, a gas giant like Jupiter.
Now, astrophysicists from the University of Texas in the US suggested that Earth-like worlds could exist in the habitable zones around binary systems that are neither too hot nor too cold to support liquid water on its surface, and thus life as we know it.
“This is an assessment of the possibilities,” said study co-author Zdzislaw Musielak. “We’re telling them where a planet has to be in the system to be habitable. We’re hoping they will look there,” he was quoted as saying by SPACE.com
The researchers used the Kepler-16 twin sun system as a starting point. The habitable zone of this system is centred mostly on the system’s primary star and extends in a region around it equal to 0.36 to 0.71 the distance of the earth to the sun. This corresponds in our system to a distance from between earth and Venus to about Mars, the researchers said.
“This work is informed by observations and it has the potential to trigger more observations,” said study co-author Manfred Cuntz. One possibility the researchers explored involved an earth-sized planet that directly orbits the binary system at distances outside its conventional habitable zone. This corresponds to a distance from the system’s primary star equal to twice the distance from earth to the sun.
To host life in this extended region, such a planet would need high levels of greenhouse gases such as carbon monoxide or methane in its atmosphere to trap warmth.