Astronomers have spotted the first-ever multi-planet solar system orbiting a binary star, with the help of two telescopes in Texas.
The discovery made by astronomers from Texas, Austin and San Diego State Universities proves that whole planetary systems can form in a disk around a binary (twin) star.
Measurement of the star's orbits from McDonald's Observatory showed that daylight on the planets would vary by a large margin over the 7.4-earth-day period as the two stars completed their mutual orbits, each moving closer to, then farther from, the planets, the journal Science reports.
The binary star is called Kepler-47. The primary star is about the same mass as the sun, and its companion is an M-dwarf star one-third its size. The inner planet is three times the size of earth and orbits the binary star every 49.5 days, while the outer planet is 4.6 times the size of earth with an orbit of 303.2 days.
The outer planet is the first planet found to orbit a binary star within the "habitable zone," where liquid water could exist.