The largest exoplanet (planet outside the solar system) ever discovered is around two miles, a distance that makes it potentially habitable, scientists said on Monday. The team of NASA astronomers who made the discovery using the American orbital telescope Kepler announced the findings at the conference of the American Astronomical Society, held this week in San Diego, in California, USA.
This exoplanet (planet orbiting two stars) and gaseous Jupiter-sized, called Kepler-1647b, also has the largest orbit for this type of planet, revolving around these two stars in 1107 days. This is the 11th exoplanet discovered since 2005. These planets are sometimes referred to as “Tatooines”, referring to the planet where Luke Skywalker grew the character of the Star Wars saga.
Kepler-1647b is further away from its two stars than any other known circumbinary planet in an orbit that “puts in the call habitable zone,” according to a statement from the State University of San Diego. In theory, this means that the planet is neither too hot nor too cold to be habitable to humans and that there may be liquid water.
However, in the case of a gaseous planet, it is unlikely that life can develop it, but this could possibly arise in some of its moons. Kepler-1647b is 4.4 billion years old and is in the constellation Cygnus, 3,700 light-years away (one light-year is equivalent to 9.4 trillion kilometers) from Earth.
The two stars are similar to the Sun, one of which is slightly larger and the other a bit smaller than our star, informed astronomers, whose discovery has been accepted for publication in Astrophysical Journal. Scientists can detect planets as they pass in front of their stars, which causes a transient decrease in brightness. This phenomenon, called astronomical transit, allows deducing the mass of the planet and how far it is from its star.
“But finding exoplanets is much more difficult,” said William Welsh, an astronomer at the State University of San Diego and one of the authors of the discovery. The Laurance Doyle Astronomer, SETI Institute – whose mission is to “look for extraterrestrial intelligence” – observed the transit of Kepler-1647b for the first time in 2011.