A third exoplanet has been found by the astronomers orbiting around the binary star system- Kepler-47. Kepler-47 has two suns and three planets. Its size is roughly between that of Saturn and Neptune. This exoplanet lies between the other two exoplanets and orbits around the two sons. Till date, it is the only binary star system known to humans which has multiple planets. This discovery was published in the Astronomical Journal this week. Binary stars are much common in the solar system than the solo stars like the sun. These binary star systems can have multiple planets around them. Scientists had previously spotted two planets circling the binary stars, but recently a third planet was also confirmed. Previously, the transit signal of the third planet was weak and so, it was difficult to spot it.
Optical interferometry of a new gravity instrument was used for spotting this exoplanet. In 2012, the scientists had seen a hint of the third planet once, but the data available that time was not enough. The orbital period of the planet was determined with an additional transit. This helped the scientists to uncover many other transits which were hidden previously. The newly discovered planet is named Kepler-47d. Its orbital plane became more aligned with its two suns and Earth and increased the transit signal’ strength. The scientists said that the data from the transits show that the newly discovered third planet is the largest amongst the three. Scientists had not expected that it would be the largest of all the discovered planets.
All the planets in this binary star system boast very low densities surprisingly. The suns and the planets are not much hot. The two suns orbit around each other every 7.45 days. The system is so small that it can fit in the Earth’s orbit. This binary star system Kepler-47 is almost 3.5 billion years old. From Earth, it is located at a distance of 3,340 light-years. One star is much bigger in size and another is considerably smaller, which harbors 1/3rd the mass of our sun.