A team of astronomers from the Harvard-Smithsonian Center for Astrophysics (USA) has discovered a new exoplanet whose orbital period is the longest known so far. It has been named Kepler-421b and orbits its star every 704 days .
“Finding Kepler-421b was a stroke of luck . The further a planet is from its star, the less likely it is to transit the star from Earth's point of view. It has to align perfectly, ”says David Kipping, studio leader.
The exoplanet in question, whose star, Kepler-421, is located about a thousand light years from Earth, in the direction of the constellation Lyra, is similar in size to that of Uranus and orbits its star at a distance of about 110 millions of kilometers , which means that the planet is quite cold, with an average of -93 degrees Celsius.
Thanks to data from NASA's Kepler space telescope, known for its many astronomical discoveries, the planet has been able to be located beyond the “snow line” , that is, the dividing zone between rocky planets and gaseous planets. “The snow line is a crucial distance in the theory of planet formation. We believe that all the gas giants must have formed beyond this distance, ”explains Kipping.
The finding has been published by The Astrophysical Journal .
Image Credit: CFA
