Planetary scientists have discovered what they claim is an unusual multiple-planet solar system containing a ‘super-Earth’ and two Neptune-sized planets orbiting in resonance with each other. A team led by Bill Cochran of The University of Texas at Austin, used NASA’s Kepler spacecraft to discover the multi -planet system.
The planets have been designated b, c, and d. All three planets orbit much closer to Kepler-18 , a star similar to the sun , say the scientists.
Planet b weighs in at about 6.9 times the mass of Earth, and is twice Earth’s size and considered a super-Earth with a 3.5-day period; planet c has a mass of about 17 Earths, is about 5.5 times Earth’s size and orbits Kepler-18 in 7.6 days. Planet d weighs in at 16 Earths, at 7 times Earth’s size, and has a 14.9-day orbit.